I don't believe it does as I recently posted a comment with a wikipedia link. It does, however require more authoritative sources than wikipedia, mine did at least have several other corroborating sources. Perhaps the auto-mod is set to remove comments without at least one non-wiki link.
They encourage people who would otherwise have linked just to wikipedia to hunt out the sources that claim comes from and use those instead.
I hope they put in a note in their comment or said thanks at least, I'd hope for more there.
They were nice about things; the PM read "AskHistorians doesn't allow Wikipedia, but .... I clarified in my OP .... Thanks for prompting the clarification!"
To post an answer on /r/AskHistorians you have to have a degree in the field in question or proven experience in the field.
I don't think that people who consider Wikipedia the end-all-be-all knowledgebase should be considered for anything.
I was not posting an answer. I was correcting an error in an answer, and I thought that showing that it contradicted Wikipedia was productive. (The automated implementation of the subreddit rules disagreed.) I thought it would be great if my comment resulted in either the answer or the Wikipedia article being edited so that they were in line; this objective was vaguely achieved.
I don't think that a subreddit that bans links to Wikipedia can be considered a good source of information.