“Birthday parties, you give your guests gifts, as a means of like, ‘Thank you for coming.’ And that translates as, like, if you’re having a birthday party, you pay for everyone to come. They don’t pay. They might give you gifts, but they don’t pay for anything. Also as like a, ‘Thank you for coming.’”
This is just another incarnation of the Russians’ famous hospitality. It would be unheard of to go into a Russian home without being offered at the very least a pot of tea and a snack. This culture is reflected into the way that birthdays are celebrated. Although we typically see birthday parties as a celebration of the person whose birthday it is, Russians see it more as a celebration of their loved ones, with the birthday as an excuse for getting together rather than a reason to celebrate one person specifically. A Russian would never dream of inviting someone to a party in his honor and then expecting guests to pay.