It doesnt. But

-People know that Halo is one of the top selling FPS games.
-But generally don't know how much a specific franchise's game is sold.

Because of this uncertainty/lack of knowledge, the former is used as the standard of comparison.

I'm a doctor, a general practitioner. I recommend working in health care, it's fun! So what will you become when you ar done with your school?

Slime, you're a doctor?? All the respect in the world for you man. How long have you been in practice?

On a different note...so there IS hope for me to still have time to be a gamer when I'm practicing? Thanks for giving me hope man! Haha.

That changes nothing. Halo isn't a good metric when comparing sales to something that's always sold at least 2 times less than it.

For a Killzone game, Killzone 3's sales are about what the franchise does (give or take 100k or so right now). Halo shouldn't be used as a way to minimize not only Killzone, but nearly any and every FPS franchise on the market. Only Call of Duty sells on comparable (or higher) levels and we know with the amount of FPS titles released just this gen, that makes it an obvious exception.

It's one of the reasons I've avoided posting much in here. The topic was flawed from the very first post (OP).

Okay maybe I was a little off. Halo does deserve it's sales. But Killzone deserves a lot more. I have to admit Killzone was horrible Killzone 2 was good but way too hyped. Killzone 3 is the best fps ever so far but there was hardly any hype. The 87 kind of took people off. It's not a halo or GT that it can get a 75 meta (gt5 prolouge) and sell over 5 million. Or be a crap game like ODST. Give the reviewers money and make it get a metascore of 89.

Thanks! I've been working for over 9 years.

Yes there is hope for you. Gaming is still my main thing in life. So what kind of a health care professional are you becoming?

Not sure if your being serious here or not.  Its pretty much unanimous in agreement 360 fans are vastly outnumbered on this site, and that their voice gets pretty drowned out by everyone else.  I mean the proof is everywhere in comparison to fans of the other consoles the 360 fans are a small minority.  Obviously the 360 will have "fanboys" and "trolls" same as any other platform.  I've never claimed their better than anyone else, just that many debates are unbalanced due to them being vastly outnumbered, thus the main reason why I usually stick up for the 360 and its fans, so the debates will be somewhat balanced.

That's absurd.  Just because the 360 doesn't win polls,  or doesn't have as seemingly as vibrant of a fanbase is not an indication of anything.  I own (2) 360's myself.  I personally don't dislike the 360, I just feel it is a whole step down from the PS3 and outside of a handful of exclusives much of it's library is generic and can be played via a PC.   This is not the 360 being 'outnumbered' this is people finding they like other consoles better than the 360. 

And so what if I'm a big Halo fan?  Does that stop me from enjoying other FPS?  Last I checked I gave Killzone 3 a 9.7 in my review, have claimed multiple times I believe its the graphics King, and have a Platinum trophy on it. I wonder can you honestly say or prove that you have played both Killzone and Halo extensively as I have?

Think carefully before you accuse and slander others as being overly biased, especially users who have a proven track record of being pretty fair for the most part. 

Just because you give Killzone 3 a 9.7 and play the hell out of it doesn't mean you aren't biased.  Which you most certainly are for Halo.  That's fine,  everyone has games they love and you have an irrational love for the game Halo in my opinion.

To the point that criticism deflected towards it requires you to make a huge stance on it. 

The problem is you are using review scores and sales as the absolute measures of quality of a game. I understand your point IF the game is selling so low that the franchise is at risk of not releasing the next version.