Only a wilful fool would dispute that racism moved from being the unremarkable default mainstream view in the western world to being a prejudice which scarcely dare speak its name. I would argue that this did not come about just because a few anti-discrimination laws got passed. A great many things are illegal and yet doing them does not put you ‘beyond the pale’ in polite society. In most circles lighting up a spliff or speeding or paying your builder/nanny/housekeeper in cash are matters of little or no account and few people would think less of you if they discovered you were doing so. Overt racism on the other hand has precisely that effect because regarding that there has been a cultural shift. To be a racist is not just wrong, it makes you a jackass in the eyes of others. Most racists are now more prone to keep their views to themselves, not because someone will call the cops and have them hauled off to a re-education camp, but because they can no longer safely assume others will share their meta-context.
And so with that in mind, it may seem trivial to rail against people who display or wear images of Che Guevara but what is at stake is far more than a battle for mere tee-shirt space. The fact that a person wearing a Himmler or Hitler tee-shirt would attract scorn is quite appropriate, and so it is really quite intolerable that fans of the mass murderers of the left get to think images of their favoured mass murdering thug makes them look cool. Why just let that slide?
Groups like the ‘animal rights’ activists PETA provide a fairly good example of ‘going to the culture’ with some success at portraying people who wear fur coats as wicked and getting that meme into the zeitgeist fairly effectively at least in the USA and UK (though rather less successfully elsewhere). So do not shrug off efforts to portray people who wear images of communist mass murderers as jackasses rather than ‘cool’ as wasted effort over something something of no account. Little things like this add up and if you believe, as I do, that the single biggest factor determining the triumph or defeat of liberty is a cultural expectation of liberty, then fighting for the cultural issues really does matter. And if the lumpen wearing the Che Guevara tee-shirt does not even know who he was, as will often be the case, then tell him in no uncertain terms so that next time he looks at his pile of shirts, perhaps he will think twice before putting it on and maybe, just maybe, look at other people wearing those vile tee-shirts a bit differently.