Of course not. But after about 22 years of gaming, I can actually tell after watching several hours of video and reading several pages of impressions. You'll have to trust me on this - I'm a greater authority on the topic of being me than you are.
Not nearly as silly as believing that a game like Gears isn't part of a certain, well-defined genre. A genre, that I happen not to like - not anymore anyway. I have an Xbox, and I have a PS2, and my favorite genre has been, for a long time, racing games. I like to try good games in all genres, and back when I had a PC and me and my flatmates set up a LAN in our appartment permanently, I played tonnes of fps games. Doom, Quake, Descent, Command & Conquer, and Warcraft 2 - these were the games we played to death. I even played a lot of the original Wolfenstein, some 17 years ago.
However, by the time I got an Xbox and Halo 2, the genre didn't excite me anymore. And still, Halo 2 appeals to me more even now than Gears does. So there. I'm not labelling, just stating a fact. This is not a cross-genre game. It's not an "all-genre" game. Those really hardly exist at all, or they create their own. It's a novel take (well, not even that) on a genre that we generally call the first person shooter. Are you seriously going to tell me that Gears is something else entirely, and that if you don't happen to like it, you can't call yourself a Real GamerTM?
The fact is that the Xbox, both 360 and the original, had the fps genre extremely well covered for a console, and it drew a lot of games coming from the PC side of things (you'd almost forget now that there was clearly a group of FPS fans that could in fact bear to play such a game with a controller rather than with a mouse and keyboard). On the other hand, if you wanted JRPGs, the Xbox clearly wasn't the place to be (why do you think that people are making such a big deal that we actually get a number of JRPGs for the 360 now?). There are lots more examples of genres that attached themselves fare more to one particular console.
This weekend, I played some more PGR3 in a store, finally on a nice Samsung widescreen, and it looked pretty decent and played ok. It's not the perfect game for me by far, but you'll have to trust me that between that game and Gears, PGR3 is much more likely to convince me to get a 360 than Gears ever will. Oblivion is, in its genre, a match for Gears to be sure, but is that going to convince every 'Gamer' to buy a 360? Very obviously not (and no, that's not because you could also get it on PC).
So, ending my rant here, no, it is not true that GamersTM have to like every game that is ranked above a nine on your average gamesite ... On the other hand, a true Gamer like me does take the time to know about all the 9+ games. And that's been my primary interest in following this game: keeping track of its historical significance in the history of gaming.
(oh, and the Eurogamer review is late)