> The golden rule disagrees.
No, that rule does not say "it is rude for others to do unto you differently from how you would do unto them"--it's about how you should behave toward others, not a justification for your negative judgment of how others behave toward you.
I agree that the platinum rule is better, but that difference is not the problem here.
I don't judge them negatively. They're working based on the available information. That line of reasoning is the exact same that I would use if it weren't for the fact that I have better information available and thus can apply the platinum rule. I don't enjoy random conversations, and would consider it rude to engage in them if it weren't for the fact people seem to enjoy them. Since they do, I try to engage in them when people try to strike one up.
If I didn't have that information (and people used the golden rule consistently and weren't just knobheads), then I would be consistently annoyed at people not following the golden rule. As long as my theory of mind doesn't include 'other people generally enjoy random conversations', my perception would be that the golden rule is consistently broken by people striking up random conversations.