Rewatching for the third time and it really is rather creepy. The advances made on Pam from Jim were way to forward and frequent. Friends don't do that, people who are attracted to one other do.
I get the plan for the show was to have them ultimately be together, but I felt bad for Roy, especially in the beginning. Roy was a scum bag himself but for different reasons, but when he snapped he had good reason.
I see nothing wrong with Jim. It's Pam who was ridiculous for sticking so long with Roy who was obviously a dumb brute with whom she had little chemistry.
shareIn all fairness to Pam, though, she and Roy had been engaged for years, apparently since they were too young to know any better. And since they'd been together for so long, she felt obligated to stay with him, almost as though they were married. Breaking up without a specific new reason would have been embarrassing to her.
In equal fairness to Roy, he seems like a fairly decent fellow in his own way. But as you say, he and Pam don't share many interests or values.
(I agree with you about Jim, by the way. He goes a little too far with his jokes sometimes, but his intent seems to be playful rather than mean-spirited.)