Your starting place is always a place of respect for yourself and the people around you. Its difficult to do sometimes, and its especially difficult when confronted with a racist, bigot, homophobe, or other person who appears full of hate. Its important to remain respectful of this person because, remember, youre an Ally, and alliance is an act of love for everyone. We've all been afraid, we know what that feels like. Make no assumptions.
Assumptions are a step short of stereotypes.
This person may have his beliefs for any number of reasons, and, as they say, you don't know until you know. Better ask than assume. Understand, but do not judge. You wouldn't want someone to judge you for having the beliefs you have, so 2. Part of me just wants to let it go, and part of me wants to ask what you meant.