not a judge, sorry
but let's see if this helps
technically speaking, the judge is about right, because both of you didn't play it out correctly
however, since both of you are guilty of sloppy play (him not not asking if you wanted to counter, you for not asking him if he was going to draw cards),
I would have asked the two of you to back up to the point where he announced the spell and the step where he passed priority
it's really hard to decide if the opponent is trying to cheese you, because he may just be a bad player
always assume that people have not passed priority and ask, especially during tournaments, if you are playing blue
once again, not a judge, my 2 cents, take with plenty of salt

hth
ps i phrase my "priority questions" [any responses to that?]
if he has no response to his own spell on the stack then it's freaking obvious he passes priority

[/i]