I don't think it is considerably worse than any other SE site. As a regular on SO, stats and a few others, almost every day I do see one or two questions completely irrelevant to the topic of the site. And I'm not even counting programming questions which are asked on SO meta instead of main site, this happens with regularity.
The issue seems to be that some people don't bother reading any rules before posting. They often cross-post it to a few different forums in hope to find an answer to their problem (obviously, in such case, they hardly try to understand the posting rules) - I did follow up such questions a couple of times and this was what I discovered.
Looking at the few questions on Skeptics main page it could seem like a jack of all trades quora-like page where you can just throw in whatever question at people. If one is new to SE concept and doesn't bother to glance at the rules (which should pop up at him or her on first visit), then, well, I don't think there's anything else which could be done. The route from landing page to posting a question or answer should be as short as possible to a new user, at the same time long enough to give some idea about how it works.
All in all, as long as it doesn't disrupt the routine of Skeptics, I'd say let it go, there'll always be some amount of random noise.