Rudeness is in the presentation, not the fact.

If you say “fuck off”, that’s rude.

If you say “I don’t do favors for people I don’t know” or “I don’t take requests from strangers” those are neutral and acceptable facts.

If you say “you can ask, but it doesn’t mean I’ll do it” that’s another neutral and acceptable way to address it if you’re willing to see what the favor might be, since some favors might me acceptable.

I tend to be willing to hear the request, but only with the caveat that I will most likely not comply. Last time a stranger asked if I could “help them”, my response was “I doubt I can, and I might not, but ask away”. They asked, and all they wanted was a light. I no longer smoke, but I carry a lighter. So I checked the surroundings and lit his cig

Years ago, I had a patient that lived in a really shifty area, and folks would approach me on my way up to their apartment. I’d see them coming and before they could reach me, I’d tell them that if they were wanting something to not waste their time, but if they were looking for trouble, they found it.

Which was rude in other circumstances, but necessary in that place at that time.

Your response was acceptable in that time at that place. Not necessarily the friendliest way of phrasing it, but sometimes being friendly doesn’t go well.