if it's a properly worn medical, N95 or better mask my first assumption is that they are ill/contagious and actually worry about their fellow human, but must go out and about. My second assumption is (especially if they otherwise appear healthy) is that they are fully brainwashed and are either paranoid or they are signaling that they are fully sheep.
either way, I feel sorry for them, not anger or mirth at their ignorance
if they are wearing a good mask poorly, or it looks weeks old or it's a cloth mask, I feel sorry for them because they are clearly mentally ill or are being compelled to wear their public fiction by someone else with a mental illness and anyone that is forced to take orders from a mentally handicapped person likely has their own serious issues.
thankfully, in this part of the country, this almost never happens anymore
This is something I don't rule out, I do recall at my old church near the end there was one woman who always wore a mask and was often the only person who did...however a couple months after it ended I learned via Facebook that she had died of cancer and was battling it at the time. Very sad, and explains why she did. I've actually once worn a mask to a show when it wasn't required, and it was shortly after I got over Covid but the CDC recommendations were still to mask, so I did...in hindsight I probably shouldn't have gone to that show at all because I was still feeling weak and wasn't having a good time, in fact at one point some guy actually checked on me to make sure I was doing well because he noticed I was sitting in the corner and didn't look well....but regardless I had a valid reason.
But if someone young enough to have X's on the back of their hands is wearing a simple cloth mask into a venue where everyone is packed like sardines and
actually getting into a mosh pit, I can't think of any reason besides virtue signaling to actually wear one. A cloth mask is pretty much worthless in a mosh pit even if they were afraid of catching a cold. (A properly worn N95 may still work, but: 1-Good luck keeping it properly fitted with all the jumping and pushing and 2-Breathing in that thing while moshing must be absolute hell.)