Mr. Pissed sounds like someone who likes to put others down because he thinks he knows everything about the game. You didnt do anything wrong he bet the minimum bet why wouldnt u call with a flush draw. Don't worry about these abnouxious people/
Mr Pissed seems like the kind of player who prefers to blame others and/or bad luck for the fact he's not the owner of a couple of dozen WSOP bracelets rather than considering it might actually be due to how well or poorly he plays.
As for rudeness at the table, the mark of a true gentleman is being able to act like one when it's tempting not to. Guess he failed that test.
Never, Never, Never feel you need to explain your hand. My usual retort (if I even give one) is "You play your cards and I will play mine, thank you very much". Then turn off your chat for a while. When he sees he is not getting any responses he will either go on tilt or shut the hell up.