I haven't gotten around to looking at any leagues in my area yet as I'm trying to improve my game first, but I'd never go back to one with an experience like that tbh. If someone wants to get so impaired they can barely play then put them in a separate pool for draws so they don't drag people who came to play down imo. Whether it's more focused on socializing or not, you're a complete tool if you don't respect your partner (if they wanna party too then by all means go ahead). Old guy is completely justified to be frustrated with the situation imo.
I don't mind if someone has a beer or two, but to the point of being trashed or using illegal substances on top of that? I'll be gone before they stumble to their disc 50 ft away. I'm sure most people would much prefer a newer player, like myself, that they can give pointers to over some nimrod who can hardly stand up. You don't have to be drunk to have fun.