Sam and Smeagol

[Cinderella]

Sam could not possibly have understood this, having a simple mind that could not grasp such matters, and having had no experience with the Ring himself (as of then).

I agree with your point that Sam couldn't understand due to having no experiece with the ring himself. However I will have to disagree with yuor point that it was also due to Sam having a 'simple mind'. While Sam was a hobbit and thus simple in nature, he was not necessarily simple-minded. (this the irony of his name Samwise which means "half-wit")

He therefore saw Gollum as just another treacherous creature, at worst as bad as an orc or minion of Sauron and at best an untrustworthy individual

This idea is essentially what I would say was the entire basis of Sam's mistrust for Gollum. He knew of Gollum's past treacheries and he knew that Gollum's desire to help them was fueled by his want for the ring. Therefore Sam was actually quite intelligent and right in his mistrust for Gollum.

Also, sam never really saw Gollum's "good side" he woke up from his sleep, and saw a creature he knew was capable of great harm trying to touch the one person that Sam cared most for and he reacted logically.