I think that's just how Reddit is. Maybe a bit skewed by the selection of subs. And unlike other big US american platforms, Reddit has a history of being lenient on NSFW. They've always discussed intimacy there, including some niche stuff like posting pictures of their genetalia and letting other people rate it... I don't know what to say, this is the internet... But yeah, use the features Lemmy offers. Subscribe to communities which appeal to you, and don't just scroll through the random pile of weird stuff and then complain it's weird and contains a lot of noise. Use the features to block and mute stuff.
I think all of this is a trade-off. We might want to embrace diversity and libertarianism. At least that's my own personal take. And in my opinion that includes letting people use the place for mildly weird things which I don't understand. Of course that doesn't translate to outright bad stuff. But I don't think we need to be a 'smoothed out' place. I believe it's better to offer some technical tools to let people coexist. And we kind of have everything in place to do this. I just think Lemmy's "All" feed is a bit detrimental to what we're trying to achieve. I've subscribed to the things I like to see and I'd say it works relatively well. It's rare that I see nsfw or cringe posts, other than the usual noise and memelords. The software takes care of suppressing that for me, and I'm libertarian enough to not mind if it exists, as long as I don't have to watch it. YMMV. If it's more than fringe, report it to the admins or the bot owner.