Wikipedia, and other sources, are not always reliable. One example which already came up on this site is with regards to this question on the derivation of Newton's 1/r^2 law from Kepler's law and vice-versa. Wikipedia's article on Principia includes the misleading phrase:
The Principia states Newton's laws of motion, forming the foundation of classical mechanics, also Newton's law of universal gravitation, and a derivation of Kepler's laws of planetary motion (which Kepler first obtained empirically).
However, in reality, what was derived (as we discussed in the question) was the 1/r^2 force law from Kepler's third law. The converse was shown in the second edition to Principia but Newton never really derives Kepler's third law from a different empirical fact.
I'm stating this not to complain about Wikipedia (which I think is doing an okay job of describing the history at a level for laypeople), but to show that it isn't always a good resource to use here. Linking to Wikipedia to show some further tangential information is usually fine. Basing an entire answer on what Wikipedia says, without checking references or other sources, should be avoided. Most answers here should ideally cite some primary sources, rather than an aggregate description like what Wikipedia shows.
So, with that said, I think we can't reasonably exclude a question just because Wikipedia has something to say on it, because Wikipedia is often wrong. We want this site to be the top authority on answers to questions about history of science, and that's simply not possible if we are copying from a site like Wikipedia. The best answers don't just copy Wikipedia's content as answers; instead, you should check their sources, extract the relevant information there, and rewrite the relevant bits to answer the question.
On the other hand, if some piece of history is so well-known that essentially everyone who has studied a particular field knows it, then asking a question of the form "What was event X?" isn't really a very good question. Alternatively, if a fact isn't really debated and is quite easy to look up, it's not a very good question. For instance, "When did Lagrange discover Lagrangian mechanics?" is trivial to look up from many sources including Wikipedia. That kind of question we do want to discourage. I'm hesitant to suggest close votes for simple questions at this early stage, because even an apparently simple question can get a very insightful answer. But downvoting questions which you think are too basic, where the OP should have just Googled it, is a reasonable, and even beneficial action, which helps us sort out what is the best and worst content on this site and set standards for future questions.