In 2020 where everything is displayed everywhere on Internet, there's no real value anymore to not disclose to a customer you've just banned why he was banned. The whole "we won't tell you otherwise someone will be able to circumvent it next time" is plain dumb, genuine cheaters / hackers communities spend a lot of time trying to do exactly that, disclosing it won't make anything worse or prepare them better, they're already there. If it's just a ToS infraction for breaking the rules without any malignant motive, then 6 months is a lot especially if you're not going to disclose what provoked the ban / flagged your account. Nowadays a lot of computer unsavvy people use a lot of programs / app they don't understand, like VPN or third-party programs. Not telling them why there's a problem is counterproductive.
MMORPGs "Game Masters", or customer support, is modern tantalum torture; it's an entry job, you get low wage, and as soon as you get enough seniority to get a decent wage, you're in the layoff cart so the company could replace your senior ass and your decent wage to a fresh ass with low wage again in a neverending roll. Regarding Blizzard it's not uncommon nowadays to get horrible customer support because there's not enough experienced / senior / personnel to run things smoothly. I'm not saying it's only a management issue, it's also what you get when you're running an aggressive cost-cutting campaign. So you get drone GM who will absolutely not give any fuck to your problem and run you down the line because who cares, or you can also get competent GM like the guys who right now give people Heroic Warfront quest completion manually because it's still bugged ingame.
Regarding this guy, he has visibility so he's using it, for people without visibility, if you're ever in a "not telling ya" customer support situation regarding a ban, just keep opening tickets, at some point your case will get "elevated" and most of the time you'll get a GM with seniority / clearance enough so he'll be able to tell you why and how that loli nude program you run to make all your wow characters look like they're from some asian hentai anime is against the ToS.