@justinas It's complicated because there are both engineering and administrative sides to the question. There's the technology, but there's also enormous human factors.
Technologically, I'd say no, it's not resilient at all to mass bot accounts. In fact, the way the system is structured allows bots to impose serious resource costs on others. That's not a good thing.
In theory it's left to the humans to decide to do things like block instances that host bots, and then the humans running those instances have to figure out ways of keeping bots out if they so desire. The human factors side of the system punts the ball downhill without any solid solution.
I've always been a huge proponent of web of trust solutions to this kind of problem, but that just doesn't exist here.
So in the end I would say no, there is zero resilience against it here.