I've left subs that seem to be largely a bot reposting Reddit content. The posts seem to get no comments and it all feels a bit empty and soulless. Plus, if we want to be something other than a straight Reddit clone then copying Reddit posts over here doesn't seem the way to do it.
Yeah, I have that fear so have been throttling back my posting. I wouldn't worry as the examples I am thinking of are pretty obvious like malelivingspace@lemmit.online. That instance has a community where you can request communities and a bot starts them. At least in this case, there is a bot that just imports the posts from the relevant sub.
Yeah, I'm really not a fan of that instance and it prompted me to go so far as to see if Lemmy has a way to block an entire instance at a user level. And sadly the answer to that is no. Though there is an open feature request but the odds don't seem great of it being picked up because I don't think the original creator or commenters on the request made a very compelling case. Now though with a lot of what appears to be single purpose instances like that lemmit one, or the big NSFW one popping up and having a ton of related communities getting created all the time it's getting to be a big chore to constantly block them individually. Especially, I've found if you try browsing by all/new, it's absolutely flooded with those instances.