Quote: I never read the issues that you're talking about, but they don't sound like good writing for the character. He'll perform experiments on people, sure, but he doesn't go after kids. I remember an issue where he said that even he still had some standards or decency. I think that it was in the 90's series of X-Men (The Claremont/Lee seeies.), back when the Legacy Virus was a big deal.
Never mind what he said. I don't recall that being said, but if it was, it was not referring to his ethics or morals. Villains say anything. His standard is to be as cruel as possible and always has been. This is
the character, and has been since near his creation. Frankly, there wouldn't be much to Sinister if he wasn't going after kids.
The character has changed over the years, but the original Claremont version wasn't going after kids and wasn't that much of a mad scientist. In some stories, he has been shown to be more rational and not so evil. It depends on the writer, but he's not usually doing anything to kids.