I totally agree and would love to hear a counter argument from your downvoters. Some of this is just semantics around the word "happiness." I would argue that it's silly to pursue a state of perpetual bliss or enthusiastic joy, but we should absolutely pursue something closer to the Greek concept of eudaimonia[1]. Which is to say, we should seek to be healthy, content, live well, and thrive. And I think even in colloquial English we often mean "happy" in this sense. "They lived happily ever after" surely doesn't mean that they had a smile pasted on their faces in perpetuity.

1. https://en.m.wikipedia.org/wiki/Eudaimonia