I don’t think there is anything “militant atheist” in the post you replied to.
I also consider myself a secular humanist, but would never describe myself as religious.
I think that normalising not having a religion would help to bring tolerance for people who have differing opinions, while calling secular humanist a religious view may reinforce a bias in some people that “you can’t be good without religion”.
Proton passkeys are stored in a password manager, which he specifically calls out.
If you have a password managed and know how to use it, you’re already a lot less susceptible to the problem that passkeys are trying to solve.
Personally, I think passkeys are great for tech-savvy users, but I wouldn’t dream of recommending them to non tech-savvy people. Password managers are still used by the minority, that needs to be fixed before passkeys are useful.