I think the bottom line is that 'RTFM' is not a professional way to reply to anything. There's no need for a "retort" when a stranger is asking a technical question - it's not like it's personal or anything.
I completely disagree. Yes, you can word it less directly by saying "Please Read the Manual", but there's really no better answer to a low-effort "do my work for me" question. Those have become more and more common, just putting the question title into Google often serves up another question that solves that exact problem, but people don't even bother using a search engine - they go directly to asking others to do the thinking for them, then complain when they are given a solution that they can't just plug into the client project they are working on.