Again, the Galaxy issued the “fatwa” on these stupid things several years ago – at the request of the patrons no less. Goats USA allows them still, I think. That’s soccer “culture” for you.
The thing that bothers me with the horns is that it totally neutralizes the home field advantage. The away fans can interpret the noise as favoring them, which they would never be able to do with the chants and singing from the Galaxy supporters groups. So any team that allows those horns to remain is putting itself at a disadvantage.