Well, I have read the whole thread. It seems to me the term "serious" has some definition problems. Some seem to be taking the term to mean you feel you are a soldier, some seem to be taking it to mean you are on a sport team. I think the "hardcore" teams who train, coordinate gear and such, are just the difference between beer league softball and competitive softball.
Taking pride in a sport and trying to improve teamwork and coordination in order to win. My budget puts me between two and three. I want to have fun, am having fun. If I wanted to be a soldier I would have signed up. I want to be part of a team who is not just shits and giggles and takes the "sport" seriously, that being said, I do not mind random skirmishes and "shits and giggles games" as well. Its all a matter of mindset. I am not trying to be a "wanna-be" I am trying to set up an authentic kit, mostly because its used in real life because it is effective, it looks better and functions better when used in conjunction to how it was designed. It is also part of the "team" uniform. Even beerleague softball requires jerseys, a minimum amount of "kit" to participate. You show up to a beer league game in a speedo and sequined tanktop, you are going to get tossed. To the mess kit comment, play a few 12 hour milsims, or two day ones, you will be glad for the ability to muck up a quick warm meal.
Even the hardcore "#3" players want to have fun. It seems to me the definition for them is just a bit different. They have fun fielding a cohesive team that works well together and looks badass fielding decent weapons that can get the job assigned to them done.
To me, again, categorizing like this, just lends more to the "Us vs them" attitude I have seen quite a bit. In the end, everyone is in it to have fun, some just roll different. Live and let live. You want to play in a milsim, respect the rules. Skirmish, the same. If you are category three, respect that skirmishes are not meant to be 100%.
I guess my ramble ends with. Respect the differences there are.