I personally don't believe it's possible to "give out" kindness, compassion, friendship solely from an utilitarian position. It would either be fake, and people feel the difference and the desired effect does not follow, or your utilitarian position is a front, in order to justify being kind to unkind people around you judging you.
Some persons (me included) suspect that humans rarely if ever act with true altruism; that it's actually a nicely dressed up form of self-serving hedonism.
And so for us, the challenge becomes how to get ourselves to act good / kind despite that. One way is to find ways to intentionally tie kind behavior to our own self-interest.
It's a rather huge theoretical distinction that at least in the West goes all the way back!
In general, one shouldn't confuse ethics itself with the whatever one might think is the most viable ethical system! It isnt a product to market. Utilitarianism is no less silly the anything else, and has its own ridiculous edge cases and all that.
It's been fascinating to read up on something about which my thoughts were only half-formed.
My best is: they are saying it is worth taking a step back and making a prioritized list of our values. If we do this, we may place "being kind" over "being productive"
I think their warning here is about: what happens in a situation where being kind is NOT productive? Will you just drop it?
I think I agree with the broad strokes of this. My rebuttal is: the comment above this was just pointing out, for people who do not value kindness over productivity, that they are not in opposition. That you don't have to pick one or the other. You can have both.
We can get mad and turn away from people who do not share our values/priorities. Or we can show them ways that our value systems do not clash and it can be win win