That website looks like a billboard. I don't even know what to click to reach the community. I mean I see the "discussions forums" link but it's still drowned in random logos, what the hell?
I remember back in the 1980s when people who liked assault rifles... liked assault rifles. Today the companies that sell 'em will go bankrupt if the Republicans get elected because then the people who buy 'em won't be afraid of getting them taken away anymore.
In all fairness, that might be your bias talking. I dont know the site but have had great talks with weaponry nerds, they generally arent much stranger then train or history nerds. And pack the right amount of pedantry to be interesting.
edit: To give just one example, /r/syriancivilwar had great discussions about armaments across as diverse of a political background as you can come up with. That is before they got overrun by propagandists ofc but the point stands. I rarely encountered caricatures among weaponry nerds while the allegation of bias often comes from people with very entrenched worldviews.
You will likely be able to check if that applies to you if you are able to word what bias you expect in such communities. And how much that matches caricatures your political ingroup spreads.
What is that based on? It's not my experience, and it seems like binary reasoning: Either no bias or all bias. Everyone lies, for example, but some are far more honest than others. Every developer writes bugs, but it would be ridiculous to say everyone's code is 'overhelmingly' buggy.
