You think that every has in in depth knowledge of celebrities and the famous, but I doubt they do. I’ve met people who’ve worn band shirts and didn’t even know they were that of a band. They had no idea what was on their shirt was the cover art of an album. Do you really think people have an awareness of his politics? I’ve never met anyone in real life who has, except one. This model probably knows nothing of his political views. If this is professional photo, then wouldn’t she have a stylist? In that case it wouldn’t be her choice of shirt.
And when has morrissey advocated for gun use? (And don’t tell me on the cover of You Are The Quarry). When has he specifically talked about it? Things are not so black and white that all republicans have the exact same convictions.