Well, i can see a number of mindset issues here 
The problem of getting attached to money is that you make less than optimal decisions by specific hand or by stack size etc. and also these different plays could as well make to someone's personal notes.
In addition, attached to money really means that your limit is too high so that you literally feel the dollars getting away by every game you play. It will also lead to another issue, of getting away for the day if you win a nice tournament (win tilt).
Proper bankroll management and lots of games will fix that issue.
it's very rare that I play a hand that I feel needs study. Perhaps that's arrogant.
Yes
You have to realize that the best players became best because they were in every forum here and there, asking and posting. Even a seemingly stupid hand could give you another view if a better player gives you his view. Closing yourself to better players is a serious mindset issue. Poker ego is serious issue. Also SNGs are more complex than they appear, especially when ICM factor gets in and you will be surprised by what better players have to say.
Sometimes I think about posting hands that I bust on for some feedback but feel it'd come off as passive aggressive.
Why are you afraid of getting labeled as passive fish or loser? If you were the best player, you would win after all and you wont asking
Unless the replies you have are outright rude, it's a chance to improve something, even if it's an ego hit.
For example, last hand I played the cut off open shoved 15bb with 6-high and I call off my 9bb stack with AA. Dude flops 2-pair and I'm done.
You entered with the best hand, that only matters. Of course that may tilt you if you play $1 games with 30$ bankroll but it will be just poker variance with a 200$ bankroll. Multi-tabling also helps you de-attaching with results but unless you're a good player it's going to hurt you. Just have a proper bankroll with money that only goes for Poker.
Perhaps you're also trying to set monetary goals which are bad when you're trying to improve a faulty strategy, which leads to disaster.
I want to defend it as more than gambling. It's a skill game, right?
Well the difference between those that say it's gambling and those who say it's skill it's the number of games they play. If you play 10 games perfect and lose the 8 and say it's luck, you're gambler because you don't get a fundamental truth of poker, which is that you should play heavy volume.
However some players do play heavy volume, however with a faulty mindset and they're still losers.
There are many crushers which actually lose even 20 games in a row in ridiculous ways, even by playing perfect; however if those players play 150 perfect SNGs a day it's not an issue, and if not by day then certainly by week or month. Unless someone puts so much volume in his game, he can't say about gambling or skill.
Those that don't hesitate to call of a 13bb shove with 10-9s.
This is a simple case of choosing your plays either by pushing or calling by opponent stats and forum really helps in such situations. 13bb is not static, it may become 10bb or 16bb against specific opponent. ICM greatly helps here, for example if you think as a default of 10% calling range when pushing against a reg, set a 20% against a fish in BB in your ICM program. It will certainly cut some hands for you to push against such fishy players.
ICM is king especially in SNGs because the payment jumps are big and they come faster in 9-man. Just reading Pokerstrategy SNGs articles will certainly help for a start