I see that you want to ignore what I wrote. It is conveyed by many things. In each country is different.

Right now, the "anti-MAGA" would be open support for LGTBI+ people and feminism. That would mean rainbow t-shirts, clothes and similar things. If you were had those traits, you would know (plus the other tells) without being told.

Your comment shows that you are a MAGA/REDpiller that wants to have sex with progressive women and is looking for a way to "look the part" without actually being that.

For people who is anti-MAGA is not difficult to show. It comes natural to them in the same way that MAGA people are in the "in" about how to show their allegiances. For example: are they going around doing the "roman salute"? to know how to convey being respectful to human rights and Anti-MAGA means show support for those things. Have you tried to wear a T-shirt with the Transpride flag? Oh, wait, that would clash with being MAGA, right? Defend inmmigrants as people? Same.

You delude yourself if you think that it is just about a hat. Sure, a MAGA hat discard you because it shows support to values that are abhorrent to progressives. Like doing a "roman salute" in a world that hasn't forgotten nazism. Anti-MAGAs show who they are all the time in the same way MAGA do. It is conveyed. If you haven't noticed, you are dense.