I am not going to tell anyone that their fun is bad or wrong. That wasn't really my point. As I said elsewhere in this thread, I am a fan of the WildARMs series of videogames, which has rocket launchers crafted from the fossils of biomechanical dragons alongside princess-sorceresses. I wouldn't mind playing in a D&D campaign like that, either.
In the post you quoted, I was responding to rustypaladin's assertion that guns necessarily would change a D&D world, when the principle examples of guns that he used were highly anachronistic 19th century firearms. Of course you would have to change the setting if you were introducing technology that is centuries more advanced than the typical D&D baseline. My central point in this thread is that there are a lot more options for firearms than that.
If you want to have guns be commonplace, but still want to keep your fantasy more or less Late Medieval in tone (like most standard fantasy settings), then 15th/16h century matchlock guns work. If you want to embrace a different tone, than by all means, do as you like.
I am not even saying that modeling guns on historic guns is the one true way. I for one am actually rather fond of how guns are handled in the Suikoden series of videogames, where they are the product of specialized knowledge similar to magic and are only in the hands of a handful of people, but are more or less semi-automatic rifles. My brother and I have even been talking about having clock-work self-loading guns alongside old-fashioned matchlocks in order to give the PCs a gun that can be used as a main weapon.