I'm sure most of those gathered for the party showed up because they weren't worried about becoming infected or too sick if they did. But social distancing isn't just about them. It's also whether they catch it and pass it on to someone who can't fight off the infection. There are numerous stories about people who didn't know they were infected, went to some gathering, and passed it on to someone who then later died.
Don't be one of those persons. This isn't just about you.