It is there— it usually just takes pages of scrolling. I heard a 2nd-hand account which said their product team leadership knows this annoys the hell out of people, know it's an easy fix, but they do it anyway. If that's true, I'd guess they're ignoring Goodhart's Law with their engagement metrics and need to re-focus on their UX, though I don't have any first-hand insight into it.

Not if you don't have Pininterest account. then you can't scroll more than half a page.