For clarification, it is never informative, helpful, nor does it ever have anything whatsoever to do with the topic of discussion, that's what makes it forced and annoying.
If it were a thread about where you grew up, where you came from, or what you do for a living, then obviously it would be welcome and interesting. Instead it's just obnoxious because it has absolutely nothing to do with the subject at hand but is just pointless irrelevant references to something that nobody ever asked about.
Furthermore, as previously stated, it's always stereotypical, so you'll never see it coming from someone employed in a business which isn't manly or exciting. You'll never see a dentist, or a chiropractor, or a cardiologist show up in a thread spouting work-related jargon, yet you'll see plenty of truckers, construction workers, engineers, etc doing so. Oh, and by the way, over the course of my life I've been employed in a bakery, sales, customer service, technical support, and security. I've also trained in a number of vocations, at one point I wanted to be a pilot, at one point I was going for a stationary engineer's license for a job for maintenance/repair of high pressure steam boilers, then I was pursuing a career as a print journalist. Yet how often have I spoke of any of those things outside of context? They were jobs, aspirations, not defining characteristics of my personality which I feel the need to broadcast as if any of them say anything about me that cannot better be expressed by simply being myself.
Don't get me wrong either, if it ever struck me as someone merely being enthusiastic about their work, then it wouldn't annoy me. It's like John Madden likening everything to Football, it's his life, his passion, not forced. But when someone feels the need to constantly reference their state/city, race, or career constantly, especially when they already have all of said information listed publicly on their profile, it's just forced and distracting.