Setting aside the technical issues for a moment, your last point is interesting to me.
One of the things that bugs me about security/privacy discussions is the rampant paranoia and misinformation, and it tends to be the louder voice in the discussions lately. I have to wonder if Protonmail being such a visible figure means that it attracts people who're inclined to fall under the aforementioned.
i.e, the people who use Protonmail for mostly innocuous reasons just don't say anything, so the poorly informed bits float to the top.
It's like apartment ratings, I guess - nobody writes a rating for a good one.
Disclaimer: I interviewed with PM last year and was offered a role, but for various life reasons didn't take it. They're pretty smart people though so I'm inclined to give the team the benefit of the doubt - I don't think any of this influences my comment above, but worth noting.