It's really hard to generalize a group on that level unless you're on the outside looking in.
There's plenty of jokes about man-bun and skinny jean wearing hipsters floating around. There's plenty of jokes about white trash floating around. I'm not sure what a joke about white dudes in general is going to look like barring the obvious case where you generalize a joke about white trash or hipsters to all of them. It's going to be very hard for a group of mostly white dudes to joke effectivly about white dudes because as members of that group they all see that group in higher resolution than that.
There's plenty of jokes about man-bun and skinny jean wearing hipsters floating around. There's plenty of jokes about white trash floating around. I'm not sure what a joke about white dudes in general is going to look like barring the obvious case where you generalize a joke about white trash or hipsters to all of them. It's going to be very hard for a group of mostly white dudes to joke effectivly about white dudes because as members of that group they all see that group in higher resolution than that.