The reason for this is obvious: they have NO INTENTION to take the video down, and will do anything they can to stop criticism. Classical Trolling.
The appropriate response would have been:
"We are sorry for this, and did not realize the sexism portrayed, we will begin work asap to move away from such advertising."
That would have been the end of the conversation. And would have boosted their cred if anything.
Trolls don't try to stop criticism. Trolls like upsetting people.