How to stop giving nasty strangers mental real estate?

Another day, another random person making a nasty sounding remark to me - I didn’t catch what he said, which I think is a good thing, because I picked up on an aggressive undertone.
He was sort of laughing at the same time, so I’m guessing he was mocking me in some way. I was literally just walking to work back from the shop after buying one of the residents a paper (it was folded over in my hand, so the title wasn’t obvious). Maybe he felt like being snarky because I was sort of laughing at the massive dog poop someone had ridden over on an electric scooter/bike (it was gross, really, but not a surprising sight around here, either). I just carried on walking in the other direction without responding, but felt a little shaky and could feel a bit of adrenaline flowing, like my fight/flight response was kicking in.
My mind was trying to analyse the few words I thought I’d understood, but I did manage to stop it once I realised, because it wasn’t going to do me any good even if I did decipher what he’d said.
Is there a way of neutralising the fear I feel when I get shouted at by a stranger? (doesn’t happen every day, but it’s happened enough that I’ve developed a mild fear of it happening. The last time it did, some guy in a van pulled over and asked if I’d seen “a woman who matched my description”. It took a second to realise he meant me, at which point he sped off and everyone in the van was screeching with laughter. I felt humiliated and just wished I could move somewhere nicer. Maybe I need a better “Jerk at 12 o’ clock Alert” radar? )
I know I shouldn’t care, but I find it difficult sometimes to not think of these people and then ruminate on what happened (though I’m getting a bit better at not doing it). It makes me feel pathetic - vulnerable, because I can’t run (old ankle injury that never really healed. Considering buying a small skateboard I could plop down and push off on!) but also helpless because trying to fight back, even verbally, could be risky. I don’t have the guts to try, either. It feels like letting them win, though, which I hate.
Ugh, I didn’t mean to make this so long, but thanks if you managed to read it all!