atomic has had a meaning for a very long time in IT, don’t pretend that it’s something made up bullshit. with this thinking we could just throw out the word mutable/immutable too, what is it my computer is radioactive and I’ll get cancer from it? of course not, because it has a different meaning with computers, and people in the know (not even just professionals because I’m not one) know it.

atomic means that if multiple things would change, they will either change at once, or if the task failed none of it will change.
sometimes these are called transactions, suse calls it transactional updates. but is that any better? now the complaint will be that suse must have transacted away all the money from your bank account!

and distros are obviously not immutable, that’s just plainly misleading. we update them, someone does that daily. updating requires it to be mutable, to be modifiable.