Glenn Reynolds says:
I DUNNO, IT’S ONLY CONJECTURE WITHOUT AN EXPERIMENT: Yep: MSNBC would react quite differently if Tea Partiers threw rocks at them.
Here's the baseline: MSNBC's Larry O'Conner gets rocks thrown at him by masked members of the race riot in Ferguson. He's quite calm about it and keeps spinning.
Now let's have the same scenario, but the rock throwers are participating in a Tea Party rally. Then we can compare and contrast. But you really don't need to run the experiment, do you?