Hm. No. Wikipedia pages on advanced mathematical concepts are intensely useful, frequently more so than any other single text you could find on the topic, because the only other way to obtain the same information would be to scavenge it paragraph by paragraph from a dozen or so textbooks, some of which are on apparently unrelated and/or even more advanced topics. (I’ve had to do this, multiple times, and it can take months and an absolutely unreasonable tolerance of frustration fueled by either youthful naïvety or sheer boneheaded arrogance.)

But that’s provided your general mathematics education is something like one or two semester-long courses away from the thing you want to learn. Otherwise, they’ll frequently be useless, and you’re better off turning to gentler introductions.

Wikipedia is not unique in this; many other technical reference books are the same, including the Springer Encyclopedia of Mathematics (a rebranded and somewhat expanded version of the Russian-language Matematičeskaja ènciklopedija), probably the best general reference on university-level mathematics ever (unsurprisingly, as a lot of it has been written by then-current or -future stars of Soviet mathematics, that being one of the few legal ways to earn additional money while holding a job in academia). Few references are good introductions. You don’t learn C from the ISO standard—or even Scheme from RnRS, as wonderfully written as the latter is.

I am quite literally furious over an accusation of a cleverness contest in a source the quality of mathematics Wikipedia ... But to direct this fury at you would be both wrongheaded and useless. Only, any environment where this kind of behaviour exists at all, in any way, is best exited as soon as possible and forgotten about. It’s just that if you happened to suffer such an environment previously (possibly unwillingly, such as in school), you may see signs of this even where there are none. The best way to avoid this false impression is probably to look not at whether some people (appear to) flaunt their knowledge, but whether others are scorned for not having such (to be distinguished from scorn for being unwilling to learn).

Pure mathematics departments are generally among the friendliest places I’ve been to, if you just show up with a question (and display signs of having tried to find an answer by yourself, even if the result is a completely arse-backwards, mangled parody of the subject). Applied mathematics departments too, by and large, but there’s a small minority of them where people are jaded by having to teach unwilling students and justify their existence to narrow-minded bureaucrats, so unfortunately I can’t just recommend them unreservedly.