I think the problem is the yelling itself, not how it's designated. That is to say, if you simply replaced all caps with italics but were still intending to in

I think the problem is the yelling itself, not how it's designated. That is to say, if you simply replaced all caps with italics but were still intending to invoke the feeling of yelling (which I consider distinct from emphasis) then your comment would be in violation of the spirit of the guidelines. The all caps are just a red flag.