There no problem with outrage being directed against people who claim that a politician is wrong. That outrage can lead to productive discussion.

I don't think a strong reputation is necessary for people prefering to watch the debates with those subtitles instead of watching the debates without the subtitles. At the same time I think that the way Stefan Schubert annotates the videos is likely to be appreciated by many people. I think this is hard to judge in the abstract without viewing those videos.