1. His credentials are literally relevant to the evaluation that he is "some guy" and therefore not able to weigh in on free speech and related technology regulation. Specifically, this is his area of interest and he is capable of giving expert opinions on this.

2. The claim in question was within the EU's press release itself, however, the EU haven't made their specific evidence publicly available. It's quite likely that others also aren't allowed to divulge specifics but this doesn't mean that they haven't seen evidence or that the EU hasn't provided any evidence.

Some guy isn't just giving his opinion, "If memory serves" implies that he has knowledge of an unreleased EU government report but his credentials seem to be of an american or maybe uk corporate lawyer and barely a professor at an american university. No reason to believe he has privileged access to the report. Though there is reason to believe he's practiced in the arts of online propaganda wars.