This is the other problem I have with these discussions. Everyone wants to cherry pick which edition they want to talk from.
@Alzrius talks about "positive energy". That doesn't exist in 5e. There's no positive material plane in 5e. That's been gone from D&D for a long time. Cure Wounds? That affects ANY creature. Full stop. Welcome to 2024. Has nothing whatsoever to do with any sort of energy.
Now, since there have been changes to the game over the years, why would people insist on lore that's no longer relevant?
Despite your numerous posts to the contrary, there are different ways to describe things that come from the same entry in D&D. Some people will have dog headed kobolds and some people will have lizard/draconic ones. When you say 'demons don't have biology', that's not supported by...I don't think by a single edition of D&D. And suggesting that 'balor aren't described as having a gender' is rather meaningless, given that humans (under the entry of 'Men') are also not described as having a gender in the MM. Mermen are though. Furthermore, several demons are mentioned as enjoying certain things to eat, but Men again, lack that mention. If one were to follow the MM, it is humans that have neither gender nor the ability to eat, while the so called fiends possess both.
As for why people insist on lore that is older, common lore is what has made D&D a shared universe. Did Tenser like your party? Did you guys end up angrier at Toves than the armanite? What happened when your party found the Wand of Orcus? It's the same as people who prefer the Silver Age of comic books or the Star Wars novels of the 90s or old Babysitters' Club books to their modern counterparts. Having shared in the experience, discussion of its lore, the what ifs and might have beens, the parts you enjoyed, the parts you didn't, etc, builds a community around that commonality. This is such a basic human social concept, it is almost mind boggling that one would not understand (or pretend so) how it works. It isn't just entertainment. Religious groups, military units, speakers of a given language, amateur scientists of the 15th century and probably millions more go through the same thing.
As the lore grows, there are those who like the new ideas and adopt them, there are those that try to reconcile the old with the new and there are those who reject the new lore. Sometimes that causes a schism, sometimes it causes subgroups that coexist, sometimes it leads to a power struggle with winners and losers. Depending on how the lore is grown, it might be done carefully with respect given to the past lore, or it might be done carefully with no respect given to past lore.
So the marilith has changed. I know nothing more than the art OP posted, which I didn't care for. It suggests a change in the lore. People
should have thoughts on that, whether they like it or not. If they don't, it doesn't bode well for the D&D community of this era. Discussion and debate are how the communities thrive. It spurs creative storytelling that improves the experience far past the table and game session.
But sure, I suppose some deviants are just angry because there are no snake demon boobs.
