Security risks?
It would take a decent a web developer two days at most to write a script to take the content from the Wiki’s database and convert it into static HTML files which can be served with no risk at all, or just point an off-the-shelf web spider at it and it’ll produce usable files in an hour. It would take a decent sysadmin a day to move the entire wiki onto an untrusted external host such as AWS outside of the corporate network which would remove any threat.
That a company with Epic’s resources would think it better to throw away all of the community effort which went into writing those guides, ruin one of the few good searchable resources on UE4 with answers and not just questions, and basically throw away a lot of good will says a lot about the reality of their community engagement.