Is there anyone older than 8 who doesn't understand this?
I disagree with the premise in the first question that anger is an adaptive display. It's as fundamental as smiling. And Sell's answer is just off the rails, ". . . we have all descended from the people who made just the right face when angry."
" . . . the emotion of anger is to bargain for better treatment."?? Sometimes I get angry at a knot I can't untie. Do I bargain with it? No.

In places he seems to argue with himself. The entire interview is ground that was covered 50 years ago. Maybe the evolutionary psychologist could move on.

His time would be better spent writing a 50 page analysis on "Amandla Stenberg (Rue in the first "Hunger Games") takes Kylie Jenner to task for wearing cornrows" (although I think Amy's simple statement covers it perfectly).

Canvasback, emotions are not just feelings; they are motivational tools. The anger may be frustration -- telling you to stop a futile task. Or it may be motivating you to go scold the person who tied some knot (boat?) too tightly for anyone to undo.

People whose ancestors survived are those whose adaptations best fit the environment -- whose adaptations were successful in helping them survive and mate.

Always amazed when people sneer at stuff and assume it is simple when it is not.

Personally, I always try to avoid being of the Dunning-Kruger effect.

Dunning-Kruger:

https://en.wikipedia.org/wiki/Dunning–Kruger_effect

Oh, and the anger he is talking about is interpersonal -- social -- anger.

To refer to what you feel at a knot as anger; (per Parrott), it's categorized under the anger domain, but it's not simply Anger. It's more frustration. Again, the motivation from your feelings will direct your behavior. We don't feel things for no reason whatsoever.

You'll find Parrott's chart here (with six basic emotions and then their nuances). An improvement on Ekman's six, Plutchik's eight, and Rachael Jack's four (with a couple of them mushed together:

https://en.wikipedia.org/wiki/Dunning–Kruger_effect

Amy, thank you. I wouldn't know a Dunning-Kruger from a Picasso so I looked it up. No insult taken.
I agree with Sell. Anger can be used as a bargaining tool. (Only if the other person cares what you look like) And there is an anger face - cartoonist have known it forever. Now we have emojis.

The claim that we have all descended from the people who made just the right face when angry struck me as odd. It echoes the claim that chicks dig jerks. Maybe Sells is just lonely. Personally I think my ancestors were charming and fleet of foot.
He also sounds paternalistic. The anger he refers to is presumptively male. I don't know what reproductive benefit women would have from being angry. I find quite the opposite.

I see he studies Criminal Justice. That may influence how he sees things. If he would go to a club he would see angry people sitting alone or being asked to leave. Nicer negotiators get in on more of the reproduction. We've had our best reproductive success in a cooperative model. It's how we sustain 7 billion people.