You do not have to do stress test with your community, it could be done with yourself as well. There are plenty of software allowing people to test their websites load, for example I checked my website and it can sustain as much as 20 thousand people reading the same post at the same time, at 20k it is very funky and not so well, that's the limit where it can be opened but I would rather not have that right now, I could increase that if it was the regular part but unfortunately I am getting like 30-40 visitors a day so it's not really that important for me.

The main point here is that when there is a loading issue, if it's from the server side they could test it without needing us, but for now it looks like a client side problem instead of server related. They could even use that stress test they do to provide proof it's not based on how many people are playing.