I think it's because there are a lot of them proportionally, as responses to the pandemic have been rather divided even within close social groups.
Try shaming party-goers in your friendship circle on, say, social media, and you might find the blowback hard going as "they" in sufficient numbers shame you back for being too cautious or controlling, and you become the pariah. Even if you're confident you're right, you can feel the loss of social capital. And who wants to be known as the sourpuss who tries to ruin other people's happy times?
Maybe feeling like losing social capital is even an illusion, amplified by the way social media distorts social group feelings. It only takes a few people to point the shame back at you to induce a feeling that the larger group sees you that way, whether they do or not, because your other social connections tend not to speak up in your defence.
If one of my gambling buddies tried to convince me to head to a casino with him right now, I'd have no problem saying, "Dude, we've been pals for a while but WTF are you talking about? Use your head, buddy." and I don't think either of us would take it the wrong way.
Drunk driving is universally agreed to be a terrible thing to do... Most people even if they have done it, would acknowledge that it was a bad, wreck-less, often youth driven decision.
With COVID the spectrum of agreement on how dangerous it is, is so much more vague. Clearly some people do not believe they're doing anything wrong by attending a maskless party. They may recognize that others think its wrong, but themselves truly believe that we are wrong and this is all dumb.
That's what's so fucked up about this situation. I really don't feel like I could guilt my friends even if I wanted to. Despite really believing they are making the "wrong" decision, I also recognize that they don't share that opinion, and that they are part of a fairly large group that shares their viewpoint. It's not as cut and dry as I wish it was and that's what's so stressful about it.
Yes, I think this is exactly why we struggle with tamping down on COVID spread. While many commenting in this thread understand how the drunk driving analogy holds (probabilistic, dangerous to others besides yourself) COVID is new enough and communication hasn’t been strong enough for the message to percolate through society.
My friends know our household is pretty strict about gatherings. We've maybe had a handful of people over, mostly one at at time, and only when it was totally necessary. My parents knew better than to even mention whatever their crazy Thanksgiving and Christmas plans were--they knew they could count us out because I was very clear with them throughout the year.
Honestly I'm not that torn and none of this weighs heavily on me because I'm not on Facebook or any other social media. I don't get bombarded with pictures of loved ones acting irresponsibly and taking risks with their lives every day, so out of sight, out of mind. My wife on the other hand is on facebook and insta all day and took 2020 much worse. Another example of social media's wonderful redeeming qualities.