[burrahobbit]

You see, Sam is not unlike a pet dog. Frodo's pet dog, in this case. A dog may react poorly to any stimulus if it thinks that it's master in in danger, Sam is exactly the same way. Sam saw Gollum as a threat to his master Frodo, and to a point Gollum was a threat. However, I would say that once he had been tamed Gollum presented only a limited threat. Gollum searved the Ring, though he may not have wanted to, and to an extent Frodo controlled the Ring (at least as far as Gollum could see. Because of that I don't think that Gollum would have done anything to hinder Frodo until the very end of the journey at Mount Doom, where Gollum's will would have been broken very quickly and events would have played out much the same way that they did.

But. But because of Sam's doglike nature he couldn't help but treat Gollum rather badly. Gollum was a killer, this can't be denied. Gollum easily gave into temptation, this is a fact. Gollum was not a good person at all. Gollum was not a threat after the Emyn Muil. Sam's derisive attitude towards Gollum was not needed at all. Sam's derisive towards Gollum broke Gollum's mind and will much sonner than it would have otherwise, and thus put both Frodo and Sam into much danger that was not needed (Shelob, etc.). And so, Sam's cruel treatment of Gollum did great harm to the hero, Frodo. I can't blame him, though, he meant well. (I can't help but feel that I have heard that before, he meant well.)