Just because you put a question mark on the end of a sentence does not mean the sentence is a valid question.

You are making a statement. And, what's more, is that you are doing it in a snide, bitchy way. If I were giving a speech at a job meeting and someone said something like that, I'd probably smack them down (gently at the meeting, and then brutally when I got them alone). Here, no one has to be gentle with you, so don't complain when they asplode all over you in response.