hackathons aren't work. They're supposed to be fun (though not everyone will enjoy them) and are attended by the younger crowd. You won't see many 40-year old engineers with kids and a spouse going there.
I'm 40 without kids and I still agree. I completely avoid hackathons at work because I hate the idea of being forced to be "creative" and doing optional work. I'd rather focus on my hobbies. I do applaud the youngins for being naive and enthusiastic though.
Every time I think I might be working too much, I hear that it's ordinary to work way more than I ever do, and I am reassured...