I think he was trying to tell you that there's a cuss word in your photo - obviously not said by you, but just as a heads-up to anyone who views the picture in case they're offended by language.
I fell out of favour with the flaregun long ago, shotgun = you get the kill on a fleeing enemy. It's vanilla weaps as pyro for me. But I am seriously tired of that argument, so let's not.
I use the Flare Gun all the time at Gravel Pit. Mini-crits FTW. Next time you're in the Pit with me CmI, we'll duke it out pro-style:axes and Flare Guns (Medics possibly included). Nice domination though.
The flare gun is a "pop, Medic!" weapon. When someone really has it in for you, it won't slow them down much. It is very effective at creating chaos with the medics, causing players to grab health packs and disrupting a rush. I like it.