Well well well... As a "semi casual" player, I didn't tried much strategus pre-patch, and just play with a few friends on EU servers on a regular basis. I must say, if sometimes Mercs are not the nicest guys (And I don't except them to be. I already have played a mercenary on other online games, and you just can't and must not have a nice guy reputation), they are fine to play with and I never had to complain myself. Good players, it's always nice when they are on your team, and hell of a challenge when you face them.
As said, they also give a lot to this game, but as it is human nature, we remember people more for what we hate about them than for what we owe them. Therefore, even if you don't have rules in your clan, you just have to know that you'll just soil the clan's reputation when, well, you act like a jerk. And it applies to every clans. It's cool that you play between friends and have fun together (it's the point of a multiplayer game after all), but you'll get the other Mercs into trouble, or make them look like assholes if you act like one (hypothetically speaking, I don't say you do). And that, there's nothing you can do about that except trying to behave sometimes. This thread is a good idea too (maybe a little troll magnet-ish), but it will be quickly forgotten : next time one of you will be trolling, it will probably be "Mercs' fault" (Generally speaking, for casual players or those who don't really know each Merc). Sad but true.
Varyag, the Risen server rules may not be the most tolerant, but they are understandable (It's a multiplayer game, you come and join a community and it's quite rude for other players to just speak a language they won't understand. Just my opinion.). If their rules were "If you speak a different language than English, we will track you down, put you, your friends and your family into camps where you will slowly perish, until we wipe the shit out of you in a gas chamber" then they indeed might be chocolate chip cookies. I guess they're not, and you could have actually discussed it if you really cared about that.
But you were taunting them there, don't say you weren't expecting that they wouldn't react, and that they would take it well. You were trolling, and that's too bad because that's what might make you look bad.
You're great players, skilled and all, and I'm pretty sure that all "Mercs are assholes" thing is overdone, from what I've seen. Just don't give "Mercs' haters" reasons to be right.