Oldpath left by his own choice. He even posted about it. He basically said that if he can't post religion in his signature line, he's out of here.
There are rules here, and it's up to the owner of the site to set and enforce them. He clarified that the rules extend to the signature line and asked to have the rules obeyed. Not sure what the controversy is here. The rules are not a matter of member vote or consensus. The offender was not blind-sided or banned. He was asked to correct the situation and decided he'd rather leave than follow the rules.