here's a list of some of them
http://www.splashdamage.com/people

I don't know your definition of "professional players" but testers don't count to them. You know those guys who play in leagues and tournaments for money ? Also organized in clans who are supported and sponsored by big companies like AMD, Intel...etc.. Players who actually do nothing but training their gaming skills the entire day. Many people out there call themselves a pro-gamer although they have no clue what this actual means. You earn money with your gaming skills (reaction...aiming..etc.).
For being a real game tester you need an advanced knowledge about programming and how the software works with the hardware. Of course you should have experience in video games but in first line you need technical knowledge to get a job as a game tester. Game tester...pro-gamer...two totally different worlds.
But back to this comment about "rolling noobs". We all start at point zero, don't we ? So we are all noobs when the game comes out. I don't know why people start bigmouthing then.

*sigh* yes they're not real professional gamers, but if they do start playing on multiplayer, they will own whatever players get on together with them, simply because they know the lay-out of the maps. so until those professional gamers find out the maps those testers will be qualified to be addressed as professionals, or at least in my opinion.

yes, we're all noobs when it starts, apart from the devs and testers, and i didn't see any reason for him to say that, but on the other hand it wasn't offensive or anything, and it could only get offensive once you commented on him saying that. so just ignoring would have been a better choice here.

I think you overrate this. Once in a while there are matches between teams of developers, tester...whatever... and teams of people that have been invited for a demonstration (usually people that work for game magazines). Although it often happens that the developers get owned even though they supposed to know everything about the game. So much for their advantage towards new players. But ok, if this is your opinion. I just don't share it and don't want to fight about it.

If his comment was offensive or not is in the eye of the beholder. You may it see in a different way than me and why shouldn't I give him a hint that comments like this may provoke other forum users ? Besides I don't see a reason why he should feel offended. My comment wasn't offensive at all and there is no way to misunderstand my message.