The headline is misquoting him, the full quote is:

“Well, because we all agree that it’s a tragedy having the school hit, and we all agree now for an investigation,” Fetterman said. “What I don’t agree with the rest of my colleagues in the House is that it’s a war of choice, or it’s dumb, or all the things my colleagues have described, you know, this operation. I think it’s a good thing, and I support that.”

Still glaringly stupid, but the headline makes it seem like he's in denial it happened. He didn't say the words "leftist" or "craze"

Edited for accuracy!