I'm not sure the types of 55's who would be "abusing" level 50's would be the one's playing lvl 50 ops. The elitest players who often abuse under-geared players are likely already overgeared for lvl 50 ops as is and won't waste their time with them. The focus of the argument to put these ops in GF is to allow players who don't have as much time to play the game experience the storyline of the level 50 ops.
I would tend to agree. As I alluded in my OP, the dread guard-geared-and above 55s doing classic ops are probably after vehicles/pets/crafting materials/achievements. Its also possible they are doing the op to help their friends or guildmates who are undergeared, but in that situation they may not be in GF anyway.
I think the risk that a person might get grouped with one or more "griefers" who specifically entered the GF queue to harass undergeared players is significantly lower than the benefits it offers to casual players.