It's a well known, but unwritten, tenet of firearm ownership that when a person wears clothing depicting a brand of firearm, one must carry the matching brand of firearm.
We can't have folks carrying Sig P220's while wearing shirts with "Smith and Wesson" written on them.
Imagine the confusion passers by would encounter witnessing a Sig Sauer snug in its holster right below the Beretta logo on shirt of the person committing such blasphemy.
Nope. Folks already have a hard enough time classifying everything from cell phones to curling irons as "Glocks"....nothing good can possibly result from the mortal sin of wearing a Glock T-shirt while simultaneously displaying a Springfield Armory XD in an OWB holster.
Entirely too much chaos would ensue with such atrocious mismatching of brands and logos. This is why it's common knowledge that worn firearms must match worn apparel.
Hey, that's the rules. I didn't make them. I'm just sharing them to maintain public decency.