The far Left won’t accept that the killer wasn’t the neo-Nazi right-winger they so desperately want him to be, so they just make this stuff up. “Christian by birth if not belief” means that he wasn’t a Christian, which might be one reason that people other than lying leftists don’t accept him as one. Trotsky was Jewish “by birth” and so was Ayn Rand, who loathed him; both were atheists. Adolf Hitler was Catholic “by birth” which didn’t seem to help the Catholics he threw into the camps very much. This whole line of argument is ridiculous.