Charles had a hard time imagining it being done scientifically. He couldn't see it being anything short of torture which lead to it. How his powers were - were so genetically ingrained - you'd have to alter someone's structure. He considered how it would be possible. He didn't find it okay, though.

Your world is much different from mine. We wouldn't...couldn't... turn other people into mutants. And he pitied whoever would have it done to them.

I'm sorry to whomever experienced a thing like that. To alter someone so dramatically... he, of course, hadn't pried enough to know that it was Steve.