I have no data/info on who all is doing this type of modding, I was just saying I understand it. The only one I know for sure that does it is /r/conservative (which I'm not a part of), but I could absolutely see LGBTQ+ subs making use of it to cut down on the spam/trolls. Sometimes you want a safe space to talk without constantly dealing with bad-faith-actors. It doesn't bother me that /r/conservative does it though I do find it hilariously hypocritical. In fact most of the time I see it mentioned it's making fun of it, not annoyed by it or mad at it.

Try moderating any medium-sized sub (or even some small ones) and get back to me. This is not as black and white as you want to make it out to be. Will some people get caught up in the filters? Absolutely but once you've seen 90% of people causing you headaches having the a single (or couple) subs in common it's not a difficult choice to "lose" that 10% to maintain your sanity.

I've had people walk right up to the line of the subs rules (breaking the spirit if not the letter) time and time again and it's exhausting to deal with. I've had about as close as you can come to death threats (without directly saying it) for temp-banning someone after repeatedly telling them to stop doing something. I've heard the cries of "censorship" for removing what is clearly spam. And all that was on a tiny sub. If I had identified a common source/overlapping interest with those people and it was easy to ban/block them I would have done it. Moderating is thankless work that I fell into (and thankfully got out of) and felt obligated to continue/see through to the end. I had no interest in "power", there was no "payday" or similar, it was just me trying to give back to my community and I got a ton of shit for it.