A couple of observations:
1) You said he was loose. So you probably don't have as much fold equity as you think.
2) I have seen this play often with big pairs to try and trick the big stack into the pot. So, even though he had a mid pair, your assessment of his range is too narrow.
3) What do you think he thought you had to make this play? If he puts you on AK he has the right price. If you have a pair like you did he has you crushed. Maybe the flat call pre was a clue to the fact that you don't have a big pair. If he knows you well and you never flat call an UTG raise with big pairs, then he can narrow your range.
3) How many players entered? How many were left? Is the structure fast? Are you close to the money? All of these factors make some players say, what the hell, let's gamble.
That being said, I like your play. If you just call the bet preflop then you play the hand oop and if he is willing to cbet and you dont flop a set you fold and lose 35k. He made a loose, but good call on you. I don't think he is an idiot. That brings me to another point. What is it with poker players thinking they are so great and everyone else is so stupid? I have made great plays and stupid plays. In poker, it seems that many times stupid gets rewarded and smart gets crushed. It's not a perfect game.
I am imagining the maniac you are talking about posting on a poker forum
about the donk who stacked off into a 4 way pot with 55 and how smart he was to pick off the obvious squeeze play.