Grammer lost a co-worker in the attack. Not sure why he'd call for understanding.
“Kelsey Grammer had some things to say shortly after 9/11 that I felt kind of implied the terrorist’s motives warranted some understanding. That was on Leno or Letterman. Perhaps it was just me...”
are you sure it wasnt David Hyde Pierce? i remember that Grammar and Pierce had a row over doing a 9/11 show on Frasier. Grammar wanted to do one but Hyde Pierce was against it for similar reasons you stated.