You get the experience you curate for self. If the people you followed were toxic, it’s not Twitter’s fault you didn’t unfollow them!
Admittedly I switched to Mastodon months back and some weeds are to be expected as I have intentionally avoided Twitter, but it was pretty well curated when I was a heavy Twitter user, and I absolutely can blame Twitter directly for the low value of Promoted content and algorithm generated content I never directly followed and cannot directly curate.
They also sometimes randomly revert you to the new one and make you manually switch back again ...