Whenever I’ve taken kids to football, I’ve told them they are likely to hear swearing, and they can use those words at football, but use them elsewhere and then they can’t come to football again.
I managed to convince my nephew when I took him, that they were singing “Joey Barton’s mother is a horse”
However, I am always conscious when there are kids around me, and try not to swear too much/often. I think if you’ve been politely asked to tone it down then you should respect that.