The most rude guy i found on steamtrades ?

yeah op talks to much didnt read to lolz

Well, people often use "sir" only when their chat is turning into quarrel.

Well, I highly doubt that. It's been over 3 months since I talked to him and he was like that. That's how he is, I'm just assuming that he got really pissed at you though. In my case, the conversation wasn't nearly as long as yours, I quickly realized who I was dealing with, told him that I was not willing to trade with him anymore and removed+ blocked him. He is not a scammer from what I could see, or at least wasn't back then, but he has exactly the same attitude.

Regarding the reputation part, you should take into consideration that the rules of steamtrades only allow users to leave feedback if the trade took place(positive for successful and negative for scam) and he can request to have negatives to be removed when they were given for any reason other than the ones mentioned in the rules. That could very well explain why his negatives are so recent.