Or wearing a "vote for Trump/Biden" t shirt.
In that situation basically everyone would agree that it would be ridiculous to say that the grocery store should ban people for wearing that t-shirt.
I think that most people would not call refusing to ban someone for wearing this t-shirt as a "political" decision.
Most people would agree that it is not political to refuse to ban someone for wearing a "vote for Trump/Biden" shirt.
If you do call that political, to refuse to ban someone for that, basically everyone would disagree with you.