Offensive T Shirt?Watch
I wouldn't be annoyed, you can wear what you want but I wouldn't have a very good impression of you.
I wouldn't find it offensive but I might think they were a bit of an attention seeker or trying too hard to be edgy. Either that or they might be someone with a very idealistic view of communism and be ignorant of the actual history.
I'd assume that they were an attention seeker, tankie or marxist.
Just as I'd assume that someone wearing a swastika outside was an attention seeker, fascist admirer of the nazis or idiotic raelian/fringe hindu trying to reclaim it as a peace sign.
An idealised, free (apart from the freedom to hoard wealth to the detriment of the community...),functional, prosperous society with communist ideals is about as utopian as it gets, in terms of life satisfaction for the most people. Communism in general is fine for a t-shirt- not really any different to a shirt with a cringy inspirational slogan, when you look at it philosophically. However, a shirt glorifying a particular communist regime, while likely ironic, could offend people who have been hurt by that regime. Communism tends to be implemented as a populist dictatorship that emerges out of economic and political weakness, creating a turbulent situation that quickly collapses from internal and external forces that have large monetary capitalist interests.
I would keep 4/5 meters away and i would assume your an ex-KGB spy and have strong ties with Russia. I would wish that you come across a fat american which has a FBI T-shirt and a MAGA cap and have a fight which would be legendary, however i would fear that a global nuclear war might breakdown and US-Russia ties could be worse than Cuban Missile crisis mishap.