I posted in "supermarket experience" that exact sort of encounter. I walked away. He was way bigger than me and what could I have done. If I was a guy, there is no way I could have taken him on.
Very few people understand violence. People who randomly want to be rude and violent are very unpredictable. They should only be engaged by people who know what they are doing and in force. If you see how many police it takes to arrest and aggressive drugged/drunk person you realise that if you are alone, no way could you.
As a woman I feel no problems in walking away and hoping they don't follow, but in a public place asking for help. As guy that might be more difficult, but there is nothing unmanly from walking away from a confrontation. You never will know what you are up against, I do not mean this rudely, it is unlikely that most FtM will ever build the muscle mass that GM's have, particularly if they have been working out from teen years.
In my late teens early 20s, I had a 1st Dan in karate. I was very good. I had few fears. I was still underweight for big open fights but it was a brave person who walked into the ring, I was very fast. I loved free fighting and as a light weight I had a rank.
These where the days when the girl was still trying to be boy

. I went to pub with friends. I went to the toilet, a big guy from another group followed me and he must have needed to make his flags, so he went for me. He lasted two heartbeats. I smashed his face on the sink taps, he never had a chance to use his physical advantages. But it was a time I was top of my game. As soon as he attacked me he was doomed, at that time in my life few people could stand against me, unless I gave them time. But I was still a 5' 8'' little guy. I still sort of regret it. I was angry and had some drinks, there was not a lot of his face left after. I walked out and his table looked around expecting to see a happy big ****, I walked up and told then to call an Ambulance as their friend had slipped and fell.
As it happened I left the country a few months after.
So where does this dribble fall in your post?
You never know who you are going to meet.
You don't have a chance against more than one
People who like violence practice. You don't
Nice people don't win.
If people are getting nasty, get out of there.
If you are going to do something do it very quickly; asking a thug time to get the Mace out doesn't work.
Cindy