Well actually you should not mix up rating and level, they are absolutely independent things, my understanding is that they really were meant to be.
Level is related to accumulated experience, the more you play the more you get, always (with exception of surrenders in 3 first turns). Of course if you play better (win, or longer games) you gain experience faster, basically.
In principle (in an ideal world) level would represent actual skills, which can be different from experience: you can have a very "young" skilled newcomer, and a dumb dinosaur that has been playing for ages with plenty of experience but not such a great brain (if you've met me in game you see what I mean - oh well I know you do, Highlander

) Now, well, we are not in an ideal world, and we all know how that rating system can be "streched" with carefull game and opponents selection, if not to say worse cheating-like strategies.
Still, and finally to the point, the rating is only calculated based on other players rating itself and the end result of each player in this game. That is, when you get killed (or when you win in the best case), there is a formula taking into account what was the rating of players that died BEFORE you (if any, hopefully) and what is the rating of players lasting LONGER than you, if any, all compared to your present rating.
This then determines how much you win/lose rating for this match result. The idea is that it is normal to win over lower rating players and lose against higher rating, so that specific situation would not change your rating much (you are already evaluated at a consistant rating considering your match result). If you lose against much lower rating players, it means your rating is overestimated and will be reduced for that result. Same when you win over higher rating, you get your own rating re-estimated to a higher value.
With this in mind, it then gets obvious that if you join a game with players all at much higher rating than yours, you can only win additional rating, or stay level, but there is no reason you should lose much, even if you lose the game, hence
highlander wrote:the higher the risk the lower the loss.
But this has nothing to do with level of players (this is also why several people have been asking for a "minimum rating" filter whe ncreating a game).
The opposite being true as well: chose a game with all low rating noobs, and be sure to lose a lot even if ending second, and not win anything if you win the game (you can actually really get +0 rating for a win, been there, got that...) This has happened to be totally disgusting to many players once placed nicely in leaderbords... At this point, either you select your games so drastically that you almost don't play anymore, or you go down much faster than you've ever climbed up...
And the other bad thing is that, with this in mind, it also gets obvious that your best strategy would be to troll the highest rated player in the game as fast as you can, kill him soon (preferably allying 3 noobs vs 1 high rating player). And then, even if this stupid strategy leaves you absolutely no chance to win the game (as others, in the meantime, have organized a nice growing region), you still gain quite some rating. And other players that did not even participate in this great fest also get rewarded, as the highest rating player died before them...
This is where such rating system badly applies to mutliplayer games (it was initially developped for 1 vs 1 games, like chess, tennis, ... where the game objective -
win the match - is not influenced by the rating calculation method), but that's another story...