I'm in no way excusing their behavior here, that email especially is terrible conduct.
However, even in the professional world, you can't be expected to badmouth someone in a public forum ( rightly or wrongly ) and then expect them to do business with them. At most, they are going to make a little money, but they might just be giving you more ammunition to use against them, if they feel your initial words are unfounded. It'd be the same as me getting up on stage after a Microsoft conference, grabbing the mic and telling everyone that Bill Gates has a lying, thieving ********, and then trying to buy a copy of Windows at the stall next to the stage.
Personally, after reading that comment, I would have refused you an account as well. I wouldn't have followed up with an email with such harsh words, but you can be damned sure that I'd do what it took to make sure that you took your business elsewhere. Esquire gets a bad rep on this forum, because they sell to the forumites. We are a bunch of picky, touchy, and whiny bastards, and we are the reason that other distributors don't deal directly with the customers. This is why Rectron will only sell to retailers, because then it's the retailer's job to deal with us, and all our complaints and gripes. I guarantee that if Corex were to sell to forumites like Esquire does, we would have the same amount of butthurt threads.
TL;DR
Esquire took offense, and decided not to sell to this guy. Unprofessional email was sent. If you want retail store service, go buy at a retail store.