Why might I not want strict and warnings?

I haven't written any significant code without them since I learned of them. (I write perl -e without them.) I don't have a case where I wouldn't want them.

That said, I could imagine code that produces spurious warnings. I could further imagine some PHB who wants no error messages in a log somewhere.

I've heard some say they turn off strict and warnings in production to avoid some overhead. I personally think this is a lousy way to gain performance.

Like you, I don't like to see code without strict and warnings. I don't want to work on it. Nevertheless, other programmers have their own minds, and I want to respect that.