That's equivalent to arguing that all black people are oppressed and should be offended by the comment; An inherently racist argument. Some people, regardless of skin pigment, genuinely don't care to clutch pearls at the slightest of slights....they understand nuance and those who declined to sign the petition realized this was not a hill worth dying (or killing) on. Rather low-hanging fruit from a morally righteous perspective. The professor's comments were a relative non-issue but torpedoing his life's work after lamely collecting a few dozen signatures was an easy win. Kudos.