Ok, first, I'm angry that these judges were downright hostile to you. As a (prior) officer of the BJCP, I assure you that we do not teach judges to ridicule the entries that way. If they can't offer constructive criticism, they shouldn't be judging. We want the contestants to see the competitions as a worthwhile experience overall. That may include reward for winning or learning what an impartial panel has to say about your entry. If there are things that they find that are not true to the style, then they should point you towards methods that may fix it or at least show you what you should be aiming your research/trials towards in the effort to improve. None of that should ever include ridicule.
There are a couple things that pop out at me that seem somewhat irregular to me.
1) I know that chicory adds coffee-like flavors and bitterness. I can't say that I've tasted it in a stout before, so it may or may not be over-bittering it and/or adding a coffee-like flavor that isn't quite coffee-like enough.
2) I don't know what good soaking the oats for 30 minutes does. There are no enzymes in flaked oats, so while it allows the starches to become soluable, that can be achieved much faster than 30 mins. This really shouldn't impart any off flavors, though. I think it's just a waste of your time. You could stir the oats in, getting them wet with the rest of the grist, and things would be the same.
3) You seem to be using the full 6 gallons of water for your mash. Are you treating the water at all, or is it just straight up heated with no minerals? If that is the case, I am wondering if all that water is pulling out tannins from the grains and especially the roasted malts. This could cause a puckering, harsh astringency in the final product.
It also might pull harshness from the chicory, but that is only a wild guess.
If you really want, I'll pm you my snail mail address. You can send me a bottle and I'll give you my honest opinion and see if I can spot what might be wrong, or I can get you in touch with another experienced judge who is more local to you.