St George was a Roman soldier who was martyred for adhering to his Christianity before it became the state religion after Constantine.

You can't blame the landlord it's not his fight and it's his family and his living, he shouldn't be the martyr and maybe he didn't realise the implications of this particular St George's Day event. .

Now if the show was in a public venue or the open air and billed explicitly for what its purpose is, like the rallies of the 30s and Rock against Racism that would be different.
My dad went to jail for fighting Mosley's fascists in the street and went out to Spain too. Sticking a badge on a guitar may not be enough