I couldn't care less about the life of a pro fighter, but I completely support Tom not continuing the fight in the face of a lifelong cheat like Gane.
With that said, I don't think the rematch goes well for Tom. There's going to be much more pressure going into it. If he wins, people will dismiss it and say he should've lost the title in the first fight. If he loses, well that just wraps it up. Even if he obliterates Gane, or beats him twice, there will be people whining about the first fight.
While random opinions shouldn't matter, I believe this will create pressure that will only affect Tom. We'll just have to see how he handles it.