How often does protonmail disable accounts? How many complaints of this sort have you found?
PS: I can see the need for mail servers to suspend accounts for spam. The post indicated that it was closed for an association with a forum that engaged in illegal activity.
Spammers often register accounts by the dozen. Spammers often throw legitimate accounts in with the bad accounts to hide their tracks.
In the war against spam, mail servers probably have to disable accounts by the dozen as well.