Ah, redesigns, the preserve of the company who has run out of ideas. To be fair, I don't think that what Meta is doing is a redesign but plenty of other companies think that you make something look a bit swisher then everyone will come back.

My experience is that people care less about UI than most designers would like to admit. Of course, nice UI is nice but people would rather achieve a task for a cost and UI is just icing. Even worse is when you change the UI/UX, people get really annoyed at that! "Where is that button I always used to click to do X?" "Oh, you don't do it that way anymore! You need to relearn what you have spent the last 5 years assigning to muscle memory but hey, the site looks cooler right?"

I mean what else would you expect if you employ 500 designers? They have to do something.