Fixing a cat or dog so they can't reproduce is way different than taking away a poisonous snake's venom sacks. The venom helps with the digestion process as well as killing the prey to be eaten.
I looked this up and Im pretty sure the venom has nothing to do with digestion and you'd be feeding F/T to any venomoid anyways. I don't see a lot of difference between this and declawing cats. I really don't see these petions doing anything really, If someone pushes this any legislature could easily say lets just ban all venomous snakes and that could get the ball rolling on other species and groups.