If you don't like those, anyone can develop a feed algorithm and anyone can subscribe to it, so you can have topic based feeds like "Science" or you can have feeds that just change the way the feed behaves like "OnlyPosts", which is the following feed but with no reposts or replies.
I feel like this is a recognizable genre of comment. I consider myself a big time Mastodon supporter and am proud to be an evangelist for it. One thing you would see in HN comment threads were these first time users claiming all the content was X where X was something very unusual, extreme, and the claims regarding what that extreme thing was would be completely all over the map. They would also be subjective, hard to prove or disprove, but also way out of line with my personal experience and the experience of others who had used Mastodon for anything beyond a trial period.
It looks like we're getting the same version of this type of comment now, except it's for Blue Sky. I've used the app on my phone and computer, followed a few people, followed a handful of discovery feeds. I can't really prove anything here, but I think whether it's Mastodon, whether it's Blue Sky, whether it's Lemmy, I feel like the most outrageous and unreliable comments have tended to be the genre of "skeptical new user sharing their first impression" style comments, which make broad brush claims as to what "most" of the content is on a given platform.
I'm not even a fan of Blue Sky for numerous reasons I won't get into here, but I've had an account for, perhaps a few months now, but, as I often find myself saying when it comes to new platforms, it is not at all my experience that I'm seeing furry porn and rage bait. If there's any one thing noticeably unique in my experience so far, it's the general lowered temperature you feel in your feed compared to Twitter.
Lemmy has some content problems, but I haven't ever noticed it nearly as bad. Mastodon is somewhere in between, but at least there's some good stuff there. Threads is definitely the chillest microblog platform but feels a bit too artificial at times. I would personally take Twitter, even at its current state, over Blue Sky all day long.