The "deep moral dimension" generally applies to group memberships that aren't (perceived to be) chosen: sex, gender, race, class, sexual orientation, religion to a lesser extent.
These are the kinds of "Group X" to which I was referring. Discriminating against someone because they majored in Drama in college or believe in homeopathy are not even remotely equivalent to racism, sexism, and the like.
People don't get to choose how intelligent they are.
A few examples (in approximately increasing order of controversy):
If you proceed anyway...