Chances are, Mr. Bar Dude does not have psychic powers and isn't thinking, "Ha, you big redheaded moron...I read one news story, and I already know way more than you!"

Actually, pretty good chance that is exactly what he's doing. Being a guy, I've..um..seen OTHER guys do that a lot. Yeah, other guys...

For the LW, consider that when the elder-splaining kicks in, it is a defense mechanism. They see you as a threat in the workplace, and are trying to stay at the top of hierarchy. And try to have some compassion, time marches on, and one day it will be you doing the 'splaining.

"Finally, there's a little secret to getting treated as somebody's equal, and it's acting the part. If some graying co-worker makes age-related cracks about your tech usage, don't go all woundypants. Laugh and tease 'em right back -- telling them they should cut the hints and just ask you directly when they want your tech-savvy millennial help with texting nudies from their side-entry bathtub."

I would caution against this, as it's a pretty overt statement of age bias, and could lead to a (valid) complaint. Fair or not, our employment laws only apply to age discrimination upwards. I've mediated my fair share of discriminatory situations in the workplace (age, religion, gender, etc.) and it's very easy to re-phrase the response in a way that avoids problems.

Self-deprecating remarks or just stick with the opening of the remark -

"don't hint around, tell me what you really think."

ARE you using your smartphone too much? If several people have mentioned it they may be trying to warn you... maybe they heard the boss complain or something.

As for the 40 minute monologues, "Sonny, you should major in physics and this is why..."
"Oh, I wish I had majored in physics but I majored in computer-simulated 3-D basket projecting and loved/hated it."

Tell them, “I’m 22, so technically, that makes me Generation Z, not a Millennial.”

I'm Gen X so I have no dog in this particular fight. But there is a larger issue in play, which is that, now that I'm approaching that age, I'm noticing that a lot of companies think they can get someone younger to do the same work that I do, at half the salary. Beware of that. True, not every job requires a fiftysomething codger. But some do. Do you have any experience in, say, coding a combustion-control algorithm for a rocket engine? I thought not. Don't get roped into doing something that is way over your head, and then be expected to put in a ton of training and study using your own time and money, and then accept the risk personally. That does not lead to management respect; rather, it marks you as someone who is exploitable.

Stand up for yourself. Ask for tasks that are challenging but not impossible given your level of education and experience. Don't be afraid to ask the old codgers for advice. We can be useful at times. (But do beware of getting advice that is four decades old and no longer relevant or useful. In my own younger days, my coworkers and I had an expression for that sort of thing; we called it the "that's not the way we did it in 1964!" syndrome. Some people in the field keep up; some don't. Learn to spot the difference.)

Feh. Women trying to explaining men to males. What is the word for THAT?

They are older guys. They are busting your nuts and some are actually trying to HELP you. Maybe you know what they are offering...maybe you don't but are too stupid or arrogant to listen.

You are being hazed, cupcake. It is an old male tradition that mommy never passed down to you. Amy doesn't seem to know jack about it either.

It isn't comfortable, particularly for one raised on 'feelz', but it's still real. Men's world isn't comfortable. You think Kavanaugh has anyone give a shit about HIS feelz? Nope. You got to be able to take the shit that bosses and women will throw at you.

Or you can keep being a sissy boy. Go to the gym. Start trying to look like a man.

Feh. Women trying to explaining men to males. What is the word for THAT?

They are older guys. They are busting your nuts and some are actually trying to HELP you. Maybe you know what they are offering...maybe you don't but are too stupid or arrogant to listen.

You are being hazed, cupcake. It is an old male tradition that mommy never passed down to you. Amy doesn't seem to know jack about it either.

It isn't comfortable, particularly for one raised on 'feelz', but it's still real. Men's world isn't comfortable. You think Kavanaugh has anyone give a shit about HIS feelz? Nope. You got to be able to take the shit that bosses and women will throw at you.

Or you can keep being a sissy boy. Go to the gym. Start trying to look like a man.

Two comments:
One on your response: I don’t think suggesting that he offer help ‘texting nudies from their side-entry bathtub’. helps him in their eyes or fits in with any companies’ policies on diversity.

Second: the comment on being ‘hazed cupcake’ obviously did not read your response which indicated he should step up.

Well, I read that response three times now and while Amy mentioned envy, patronizing, mansplaining, arrogance, dress up and assumption of status, not once did she touch on hazing and male social dynamics.

Essentially, this guy needs to put up with some shit to be 'one of the boys' and he EARNS his right to be listened to.

Alas, if zhe doesn't show respect, maybe learn a few things (because we all know college teaches EVERYTHING to know about a job), and does the shit work as the new guy (just like all these other guys had to do when they were him), he likely WILL face more guys trying to scuttle his career as a Know It All PITA.

Good luck with that target on the back, cupcake.

The other way out of this is to pick up a mentor. Pick an old guy, give him respect and it might astound you on what you thought you know which isn't true, cupcake. He can also get you entry into the channels of power that you frankly haven't earned yet.

I say this as a man who has actually had to traverse these male domains and not as a woman who has been self employed for decades. There are some things that credentials and studies don't teach you.

So take that as you will.

As a GenX'er that's had to navigate this, keep this is mind:

1) MOST of what you are experiencing is being done with no malicious intent. Don't assume the worst from the occasional 'Cliff Clayven' lecture.

2) Hold onto your sense of humor. You're also allowed to crack the occasional joke and for what its worth the side-entry bath tub was pretty funny.

3) Yes, there are guys that are bitter under achievers that are NOT doing this in fun. Just like in grade school there will always be the kid that has been left behind 3 years that can dish it out but can't take it.

They will often hide behind their "years of experience" and will fight tooth and nail to avoid giving any constructive or useful advice.

At then of the day, work on your strengths, develop your weaknesses and do your best to be an asset to the people around you.