So today, I asked a question on UX and received the following comment about this being a legal issue and not being allowed on UX. Why wasn't this post migrated to the Legal Stack Exchange? How do you migrate and why isn't it done more?
One comment saying a question should be migrated doesn't mean it should be. People say and think all sorts of things; they aren't always right. Others on your site might disagree, or it might sound plausible but it turns out the other site has guidelines that the question doesn't satisfy. If a question gets migrated in that state it'll just be closed on the other site. All that bouncing around is frustrating for the user who asked the question, and we shouldn't be yanking the question around unnecessarily.
Migration is part of the close-vote process currently, so if voters (or a moderator) agree it will be migrated. But if the question is on-topic where it was asked it shouldn't be migrated even if people think it would fit better somewhere else; if it's on-topic here, answer it here.
You as the asker can re-ask your question on another site if you agree with the suggestion, though this is a little controversial and you need to avoid crossposting the same question on multiple sites. In re-asking you'll probably need to do some editing to tailor it for the site where you're asking it, so check out the site's tour and on-topic help. If you re-ask your question elsewhere and can't just delete the original, be sure to indicate that you've done this -- a comment with a link to the new question, for example.