I'm going to push back the idea that something shouldn't be included just because some people don't like it. I don't have to "get it" for that.
And I haven't seen a lot of people argue that games shouldn't deal with those subjects. I'm not against criticism.
@Justice and Rule seems to have hit the answer here better perhaps that I could. I'd just ad that the whole "people don't like it" is incredibly reductionist and frankly insulting. It's like saying that Jews "just don't like" the Nazis. Not wanting to include fantasy Auschwitz in mainstream RPG's probably shouldn't be reduced to "people don't like it". There are really, REALLY good reasons not to do it.
Same goes for including slavery as an institution in a setting. Again, we have to recognize that the hobby (as in playing D&D as a hobby) as well as fantasy as a genre has been INCREDIBLY tone deaf for a very long time. Pretty much until after 2000, and really, even 2010. 20th century fantasy was often outright hostile to anyone who isn't a white dude. And, even when it wasn't outright hostile, it was still pretty unwelcoming - look at the reaction to including black halflings in Ring of Power on Amazon. In the 2020's, the color of a halfling was actually an issue.

Hell, just this year, the color of The Little Mermaid is an issue.
So, no, it's not just "because some people don't like it". These things have real impact on real people who actually WANT to be part of the hobby.
Let me get personal for a second. My children are mixed heritage. Lovecraft pretty much specifically calls my children monsters that should be killed. Now, I do not want to remove the Far Realms from D&D. I have zero problem with the Far Realms and think it's a fantastic idea. Tentacled monstrocities? Gimme more of that. But, I do think that Lovecraft's name should be removed from the 5e PHB's list of inspirational reading. I don't feel that it's a good idea to tell new gamers, and people who are new to the genre, "Hey, you should read this guy to get you in the right frame of mind to play some D&D." There are tons of other authors out there that are just as influential as Lovecraft on the genre and on D&D who aren't raging bigots. We don't include Bill Cosby in lists of inspirational comedians, nor do we include Jimmy Saville on lists of musical inspirations.
So, would you say that I'm being unreasonable here? That I'm only saying this because I "don't like it"? I certainly don't think so. I certainly would not tell my children, "Hey, you want to play D&D? Here's Shadows over Innsmouth. Yeah, I know that it's a thinly veiled allegory directly aimed at you, but, hey, you should read it because, well, not liking it isn't a good enough reason."