Actually, a more important question is why were these people granted visas by the Obama administration?
From all available reports now in all the media, there was nothing illegal about the particular meeting that has the left in an uproar. Because of the utter lack of media and law-enforcement interest in the nefarious dealings of the last administration,(specifically, the many unanswered allegations against HRC, her associates and the behaviour of Obama himself, post -election)a reasonable person could only conclude that there is some underhanded attempt to disrupt the normal course of events, following a Presidential election. No votes were changed, no money paid to "rig" voting machines and the only intimidation seems to have come clearly from leftist liberals, pre and post election.