ALMIGHTY T-SHIRT

I heard that some Rock or Heavy Metal bands sometimes dislike each other and the fans of those bands avoid wearing the adversary's band name T-shirt when they go to the show.
My friends said you can wear an "Almighty T-shirt" at every rock concert, for example "Iron Maiden"'s.
Most of the Heavy Metal and Hard Rock bands love and revere Iron Maiden, so if the fans appeared in an Iron Maiden T-shirt, it wouldn't incur anybody's displeasure.

In October, I saw a show by a group with two Japanease Heavy Metal singers.
In the event, they sing their original and '70 to '90's mainstream Japanese popular songs. They organize the recital in a small venue periodically, separately from the extravaganzas of their own individual Heavy Metal bands.
The people gathered in the venue are grown-up enough and sofisticated at a level appropriate for their age, so all of them fix up to go to the show. I also considered my clothes and my friend and I had on Japanese summer kimonos at the show last summer.
However, at this Autumn concert, I was wearing a MEGADETH logo T-shirt because I had some work in an exhibition hall for my business before the show.
I felt a strange premonition when I put on the T-shirt, but I thought no one would care about my wearing it and I cast aside the feeling.

In the show, one of the two singers played trivia which I accidentally answered. He said he had a prize for me and asked me to come forward.
Then, the other singer stared at me ferociously (as I shrunk) and said "How could you wear a MEGADETH T-shirt at such a pop recital!?" Then I guessed he only read my T-shirt logo and didn't stare at me, but my favorite singer addressed me for the first time, "Geez", as pointed out on the T-shirt. The first one responsed with "Oh! Why don't we sing 'Symphony of Destruction' next time?" and made the people giggle.
I felt glad the T-shirt elicited laughter. Also, If I had put on nice clothes, he would never have said anything to me.
I kind of worked out my hunch...

At a later date, I told this story to the MEGADETH-fan friends and they said I could wear the ALMIGHTY T-shirt.
Uh...I don't think the matter was the MEGADETH T-shirt... In this case, HEAVY METAL T-shirt is the issue!