Personally, I don't think making that thread was smart.
I agree. At the end of the day I can see where they were coming from, on the face of it it may well have looked like spam to them. I'd certainly have to think twice about whether such a post here was spam or not coming from a first time user.
I'm not saying their reaction was correct, but realistically if it were me in your situation I would've contacted a moderator, explained the situation, and perhaps complained (formally) that I didn't think their methods were fair or very reasonable - perhaps asking them to introduce some form of warning system before an outright permanent ban. You'd be surprised at the reaction this approach has sometimes - it's definitely got a higher success rate than starting other threads saying how crap they all are, and may even get an apology from some of the more reasonable mods / members.
I daresay some members of that forum are looking back at this thread now and thinking they did the right thing. In a jokey sense or not, talking about spamming them, going to 4chan and creating other threads slagging them off really isn't going to give the best of impressions...!