Well, a jabroni used to mean a jobber, a wrestler that's there just to lose, but make it look good.

In other words, it's someone with enough wrestling skill (and pro wrestling is genuinely a skill set, it's essentially stunt work) to make a big name wrestler look like they're extra good be virtue of having defeated the jabroni.

However, that was more or less an industry slang term. Jobber was supposedly used in boxing as well, and got picked up by early wrestlers, then spread among them and stayed "jobber" well into the eighties at least (and I can personally confirm that some of the wrestlers of that era used jobber, as I knew some of them to a degree, but that's a different subject).

Now, when it turned to jabroni within the wrestlers and the companies involved is more murky as best as I've ever found out. What is certain is that the term came to general awareness outside of wrestling when the Rock was using it as an insult. To the best of my knowledge he was the first wrestler to use jabroni on screen. He was certainly the first to use it extensively, and the one that spread it into pop culture.

So, somewhere between the late eighties/early nineties (when I met some wrestlers enough to have friendly chats with after turning down offers to be a jobber) and when the Rock started using the term jabroni publicly, it had become the predominant slang term within the wrestling community as well.

Now, my contact with wrestlers was pretty minor, it wasn't like it was an every day thing. We weren't friends, we just interacted. But one of the conversations in specific was basically that I could go to a training camp and work as a "jobber" for a few years, build up to maybe being in a more prominent role. And the term was used in other conversations as well. Being young at the time, I had to ask what the word meant, though context did make it pretty obvious.

But, after the Rock started using it as an insult, it has taken on other meanings in common use. So I had to read through the comments to see what you meant lol.

In truth, any social media platform does need jabronis in both the sense of regular users just doing their thing on the platform, and in the sense of some assholes making it a less comfortable thing.

It is my opinion that most people prefer to have someone to point to as bad. Having some trolls, assholes, and "class" clowns around keep a given platform from being boring, and allow the jabronis that do the day-to-day posts/comments to feel better about it.