I'm going to drop my friend who has become a militant vegan
Why are you dropping him as a friend?
My not being vegan has created problems between us.
It isn't okay to end a friendship due to a seemingly petty issue.  However, are there other issues going on?
I just can't believe his views and values on certain things especially meat eating. I'm done with him
If you value the friendship except for the new diet and values, you should try to save it. Can you avoid get togethers that involve food?  Maybe you could go hiking together instead.