I still mask, I think COVID is super serious and I work with immunocompromised patients in a hospital, and I take public transit, so it's just generally a good idea. I am very, very, very vaccinated, but I'm still not comfortable unmasked. Two angry men on separate occasions have made comments to me about masking and how I don't need to do it. I just stare right through them and ignore, but why are they so angry? It does not affect them in the slightest, and if they think I'm stupid have at it.
Just tell them you have cancer and are immunocompromised. That usually shuts them up. Irrational people are not worth arguing with and sometimes this makes them think twice about harassing other people.