“What has McMaster done that you don’t approve of?”
Well, for openers, he’s an arrogant a$$hole who is disapproving of his boss! Just like Tillerson. If you can’t be a loyal servant, you need to be gone. Being a Presidential Advisor or Cabinet Secretary doesn’t have among its duties to $hit on your boss any time he does something with which you disagree! These jerks have such big egos, they are forever tripping over them.
Each star seems to up the probability. (Remember "Stormin' Norman"?)