Well, assuming the story is true and he did go out hunting... I imagine Seagal is more against overt cruelty to animals than he is interested in being a vegan. Believe it or not, it IS possible to eat meat yet still be compassionate towards animals. If you kill with minimum pain caused to the animal and make sure you use every part of the animal that you can so that nothing is wasted (food, pelt, bones, whatever you can), then personally I see nothing wrong with it. Hunt to eat- it's a way of life that people have all over the world. At the same time, I do not doubt for a second that Seagal would hate "unnecessary" types of hunting such as the cruel fox hunting practiced in some parts of the world.
And besides, am I remembering it wrong or was he clearly eating some kind of baloney/meat sandwich in the cafeteria in Exit Wounds? either way, I guess I just always took him for a meat eater... Regardless of what Buddhism says, the only way he would be contradicting himself would be if he ever clearly stated that he doesn't eat meat, which he hasn't ever stated AFAIK.