I'm honestly probably more guilty of this offense than anyone else on this stack.
What I would encourage is everyone (myself included) to at least make more of an effort to follow the little reference notes Wikipedia puts in its text, and use those instead of the actual Wikipedia text. Among other reasons, Wikipedia text can change drastically as time goes by, whereas the sources should not. I can tell you from experience that fixing a years-old answer you hardly remember writing when its link is no longer any good is a real drag.
That being said, Wikipedia is all about condensing said sources into a short, coherent narrative on the subject (of the page) accessible to non-experts. The overlap between that and what needs to be done in an answer here is so great, that very often Wikipedia is far and away the best source I can provide. I'll follow the source links there, but very often they don't tell enough of the story, or far far too much of some other story to wade through to get the one relevant nugget of info, or both such that even seeing that nugget requires knowledge that a novice may not have. This would require me to duplicate a lot of the glue text that the Wikipedia article provided. Doing that would be a duplication of effort, cause insanely boring expansions of my answer, and IMHO be morally questionable.
So I think there are many situations where a Wikipedia link allows me to give a short coherent answer, at the expense of being twice removed from the sources rather than just once. But at least this has the advantage that the reader has multiple layers of detail through which they can chose to dive.
Reading back through this, its coming off as an unmitigated defense of "Sola Wikipedia" answers, and I don't intend that. I agree with the question that we have a problem with those. I just want to argue that Wikipedia links themselves are not the problem. Lazy answers are the problem. If you can't contribute any more in your answer than "Go read this ...", then you should just leave a comment instead.