I’m assuming these 3 are okay with the government paying for the pictures??
If the teacher in question had said 'how do you feel about your tax dollars being spent on non essential things under the National Endowment for the Arts such as homosexuals taking pictures of other homosexuals', he would still be in trouble.
There is no way to be critical of the agenda of some groups in this country without consequences.
However a teacher is expected to at least encourage the students to look critically at policies such as NEA spending when the country could use that money for other things, such as (fill in with an explanation).
Why that sounds like a good homework assignment for students in a real school.