Do people trust Protonmail email users?

An acquaintance recently said to me he thinks the many people don't trust Protonmail users, citing that they're untrustworthy, seen as likely scammers etc because of the encryption Protonmail uses. 

Is there any creditable truth to this paranoia or is he talking out of his posterior? 

I think if anything, Protonmail users should be regarded as safety conscious, it's ENCRYPTED email for crying out loud; good or bad people can use it just as effectively or as poorly as unencrypted email. *Shakes head*. 

What do YOU think? Can Protonmail users be trusted, is my acquaintance correct or is he a lunatic talking utter codswallop?