Considering your 9:20 isn't even worth a sub 15 5k, I'd stop being cocky towards someone who is much better than you. The guy's advice about hammering a LR is legitimate, it's way too fast for your level, and even then, 12 mile LRs aren't the best idea for 2 mile training. He could've been nicer, but I would just should just brush it off and consider the advice for what it is.
Without being rude, it looks like you could benefit from a couple things : your workouts have slight positive splits, your first 2 mile race had a big positive split, and you got kicked in the state race (maybe they were better runners ? ) I'd start workouts a bit slower, focus on closing them harder, don't "go the well" too much in a short interval of time and keep the long runs at 6:30, not 5:45. I have teammates capable of running sub 14, low 14s, sub 4 miles, sub 4:10 ... and our long runs are run at 6:15-30 pace. Progressions might get down to 5:30-40 average for 8ish miles, but then again it's in control. It's also my opinion that hard long runs are not very useful for 1500-5k racing, but that's another debate haha. 1500-5k pace work is really what matters, because you just need to be able to hold that pace for some time.
Anecdotally, the guys (around 8 or so) I know who hammer their LRs at 5:30 for 12+ miles consistently underperform in races. That kind of work is good for a marathon and 1/2, but when you're racing for 4-15 minutes, it does more harm to your body than good.