We may not like it but the biggest one's are in the metalcore community like Falling in Reverse Knocked Loose Darko US and SpiritBox.

I'd say the most popular band shirt I've seen here is Pink Floyd, usually DSOTM or The Wall covers, and they're usually old age pensioners.

It almost brings a tear to my eye when I see someone wearing anything to do with rock let alone metal. Saw someone wearing an ACDC t-shirt last week and my guess is they probably didn't even know it was a band name.

I remember I wore a Dying Fetus shirt to school and I had it on for like 10 minutes and they made me wear it inside out hahaha.

When I was in high school the metal kids were very cliquey. There were soooo many The Black Dahlia Murder fans it was crazy.

And meeting someone not into metal is always an opportunity to make them discover new stuff as well (and to discover new stuff yourself)

When I was in the US I only met one person roughly my age who listened to metal, but I'm sure there are more, although the religious background might have a negative impact