The thumbnail is using the political compass as a way to assign well known personalities to political ideology. Lenin for authoritarian left, Trump for autoritarian right, Elmo for liberarian right and ?/nobody for libertarian left. We could discuss these placements, but the main point is that for libertarian left aka anarchism there is no leader assigned

Also thumbnails might be different for different users because of A/B testing from YouTubers or just normal updates/changes to the video by the creator