@Dinsdale I don’t disagree with your conclusions, but I can’t agree with making morality solely up to the individual. If people are free to make up their own, there’s nothing preventing them from creating one that just lets them do what they want, regardless of harm, and then there is no basis by which to judge them as wrong, no means to prevent them from causing harm.
Morality has to be something discussed and agreed upon. It is society deciding what is best for itself. It is people arguing from first principles what we should do to cause less harm. It is pointing out inconsistencies and special pleading. There is some actual moral truth we are trying to find here. It’s not just what people subjectively think as individuals. There have to be some minimum standards of what is moral, with people choosing to go beyond that.
To respond to the OP:
You are inherently morally responsible for the foreseeable results of your actions. That’s just inherent in the concept. However, it matters how many precautions you take. You’re vaccinated (and [will be] boosted hopefully). Since you mention maskholes, it sounds like you’re also masking up. Those two things alone reduce the risk to other significantly.
Then there’s the fact that people who are there chose to be there. They chose to take the risk. So any spread here is something they decided was worth it. It’s their choice to take the risk, and their moral responsibility for who they harm.
No, the place where your decision to choose a place with antimaskers for recreation (rather than, say, a game night at home with your family) is when you might spread it to others who have not chosen to take the risk. That applies in less recreational situations, like your shopping. So one thing you could do to try and offset the risk of the game night is to avoid shopping, especially within 3-5 days of game night.
Ultimately, where it is up to you is about how much responsibility for someone having died you are willing to take on. You should be doing the things the scientists say. And, if you’re going to take on extra risk, I’d argue you should try to offset that risk in some way.
The fact is, the bulk of any death is caused by antimaskers, not you. They’re the ones refusing to do anything to stop this sort of thing. You are significantly reducing risk, by orders of magnitude. You are almost certainly below the societal minimum I described above.
Oh and long COVID is far more likely to happen with more severe and longer cases. The prevailing theory is that the virus or the immune system cause lasting damage. The former is more likely the longer the virus is there, and the latter is more likely with heavy immune response. Vaccination reduces the likelihood of both, even if you get infected. It’s sufficiently less likely that I consider it just part of the “getting COVID” calculation, which I obviously do not want to get. I think of it the same way I do the loss of taste and smell, which sounds absolutely awful to me. Or severe flu-like symptoms.
If you didn’t worry specifically about chronic fatigue syndrome before from viral illness, I don’t think it makes much sense to worry about it specifically here, given the mitigations you’ve chosen.