I don't think it is healthy for the hobby, or beneficial to peoples creativity, to be this afraid of setting flavors. Again our bar is probably different, I tend to take an approach of we should trust the audience to read things charitably enough and have enough of a nuanced material that they aren't taking offense at something that merely has the optics of potentially being offensive, versus something that is genuinely offensive. That bar is going to be subjective of course, but I would say it needs to be set at a reasonable place, so designers, writers, etc can still be creative and it doesn't feel like they have trope police looking over their shoulder all the time (I think that is a pretty impossible situation to be truly creative).
Also I don't think shifting those choices away from the core book, if they are still objectionable to people, really does much. If people are going to object to something, they will object to it. In your spelljammer example, which I haven't really followed closely so I am not especially suited for weighing in on the specifics, seems to have gained tremendous traction on forums and on twitter, yet it has nothing to do with he core book.