[Theyknow]

This may be a matter of free speech. If the students don't follow what he teaches then he can't very well recommend them, can he? If the situation were reversed I wouldn't expect the Creationist to recommend a student who didn't believe.

[tallhappy]

No. You are making the mistake that belief is equal to knowledge and understanding of the subject matter.

He had to ask them directly if they believe in a creator or not. It was not apparent from their tests or papers.

It is the same as asking if your favorite color is blue and refusing a recommendation over that.

[RobbyS]

Then he should say, "If they reject what I have taught, then why ask for my recommendation. Let the grade they made in the class speak for itself."

[Stultis]

If the situation were reversed I wouldn't expect the Creationist to recommend a student who didn't believe.

It is unlikely the situation ever would be reversed. Every creationist org or institution I have ever known of has a "statement of faith" of some sort that must be signed up-front. I.e. "unbelievers" are weeded out from the get-go.