He's sharing personal information to the forum which makes him vulnerable, in an attempt to cope with and learn from a serious mistake. He's explaining why it happened, which doesn't need to be taken inherently as deferring responsibility or fishing for sympathy posts. He didn't go "LA LA LA I DON'T GIVE A FUCK WOO DRUNK DRIVING IS FUN," he was inexperienced with dealing with being downtown drunk by himself with his car, had an anxiety attack and didn't think clearly, and let himself get intoxicated enough that his previously established conditions for going out that night with his car got thrown out. This is because drinking causes you to make really stupid decisions that you wouldn't otherwise make, and it usually takes experience in hindsight with how you handle your drinking to know when you need to cut yourself off for the night and also overcome whatever your inebriation is telling you is okay in the moment.
Drunk driving is not good. No qualifiers. Lots of tragedy results from it and as an adult with awareness of this, with a sound mind it should be an easy enough thing to weigh against some inconveniences with your social life on a Friday night. Bottom line, though, is that if you don't live in an area with infrastructure set up to handle everyone's safe return from nightlife to home, drunk people will make stupid impulsive decisions en masse and drive back intoxicated, because the point of alcohol is to make you irrational and impulsive.
He's a fallible human being, like we all are. His intent matters here, which he shared in vivid detail, and whether he takes responsibility and doesn't let it happen again matters more, which remains to be seen, but given the length of the OP I think he's taking it seriously. A ton of drive-by posts attacking him with holier than thou attitudes about the concept of driving drunk is obnoxious and immature and pointless in itself. Most of us probably know someone who has died or been killed by a drunk driver. He made a mistake, an unacceptable but very common one, and is owning up to it. Now he has a wake up call and a record, and fortunately no one was hurt in the process. That's a good starting point for cleaning up this mess, probably highlighting the importance of sound mental health and seeing someone to help with his anxiety issues, and to mature overall. The OP doesn't diminish his character to me. It's what happens next that matters.