There is another strategy than asking them to remove it, though. Ask them to qualify it. I've done this in the past (a long time ago, mind you, and in the UK, where employers are still somewhat bound by decency as well as law). I was asked to sign an extensive NDA for a short period of employment, and I agreed, on the condition that I could decline to join any meeting that wasn't strictly related to the project I was hired on, and that the same NDA bound them when discussing my personal projects.
There is another strategy than asking them to remove it, though. Ask them to qualify it. I've done this in the past (a long time ago, mind you, and in the UK, where employers are still somewhat bound by decency as well as law). I was asked to sign an extensive NDA for a short period of employment, and I agreed, on the condition that I could decline to join any meeting that wasn't strictly related to the project I was hired on, and that the same NDA bound them when discussing my personal projects.