i generally won't play lower-rated players but sometimes, it's hard to get a game if you narrow down the rating range so much. so now i get owned by 1500s and 1900s alike in bullet. in a long game, it's a bit different; i'd rather play 1700s and up.
Do You Generally Play Lower-Rated Players

I always play against random players. The average is a little under my orn rating. I guess there are a little more of those so it's not strange I guess.

I am not sure where you are getting the stat that most people play people lower rated than themsleves, but I can assure you it is quite impossible.
It is just like saying "Most people are below median intelligence".
Every player on chess.com has stats listed like:
Current: 1518 Highest: 1569 (30 Dec 2010) Avg. Opp.: 1420 Best Win: 1775 (lethalpawn) Games: 658 (317/313/28)
This says the player's current rating is 1518. His avg. opponent is 1420, which suggests that he statistically speaking plays opponents rated about 100 points lower than himself.
I rarely see a player who's current rating is below the avg. opponent rating like this (mine):
Current: 1496 Highest: 1524 (24 Sep 2011) Avg. Opp.: 1522 Best Win: 1819 (Maz0008) Games: 1,457 (504/864/89)Everytime you, or anyone else, plays someone lower rated than you, than that person, by definition, is playing someone higher rated. Always and everywhere. No exceptions.

I just play whoever accepts my open seek.
Same here.
One can't help who accepts! You can't just say "no"

im amazed at the low IQ everyone is showing. Your avg opponent rating its lower than your rating because you improved , you started at 1200 playing people around your rating your rating went up as you won games, thats why your avg opponent rating its lower than the avg rating the people you play now that you are within your true rating because you will always have your past history .... whatever...

I personally only came on chess.com a month or two ago, and haven't played chess for 30 years prior to this. Initially my rating hovered around the 1200 mark for a couple of weeks. Since then I have slowly been improving so I am now headed towards 1600. As a result I am currently in a chess.com tournament for 1200-1400 players AND another for 1400-1600 players.
Due to this rise, obviously my average opponent played to date will be lower than my rating. This will eventually change. However, online games take a long time to finish in a lot of cases, so there is a lag. I could be taking on higher players than myself all the time, and my average player played against will be lower than me, if I keep raising in rating.

Lets assume there are only four players on chess.com with the ratings : 2500,2000,1500,1000.
Someone show me a way these four players could pair up so that "most of them" are playing lower rated players.
...queue chirping crickets...

@InvisibleDuck LOL, quite obvious, crickets or not. ;-)

A few more good responses, guys. Thanks so much.
Again, I'm no chess pro, but it just makes sense to me to play opponents slightly better than yourself by setting your seek to only accept opponents rated about 50 points or more higher than yourself.
If you're rated 1000, set your seek to only accept 1050 and up. When you improve and reach 1100, set your seek to only accept opponents 1150 and up.

Lets assume there are only four players on chess.com with the ratings : 2500,2000,1500,1000.
Someone show me a way these four players could pair up so that "most of them" are playing lower rated players.
...queue chirping crickets...
2500 plays 1000
2000 plays 1000
1500 plays 1000
---
I can do maths, me.

im amazed at the low IQ everyone is showing. Your avg opponent rating its lower than your rating because you improved , you started at 1200 playing people around your rating your rating went up as you won games, thats why your avg opponent rating its lower than the avg rating the people you play now that you are within your true rating because you will always have your past history .... whatever...
Like I said, you can't help who you play.

Lets assume there are only four players on chess.com with the ratings : 2500,2000,1500,1000.
Someone show me a way these four players could pair up so that "most of them" are playing lower rated players.
...queue chirping crickets...
2500 plays 1000
2000 plays 1000
1500 plays 1000
---
I can do maths, me.
Lol! And not a cricket in sight.

Well since the average opponent takes into consideration all your games, it makes sense if your an improving player. Last year I was around 900 ish and now 1250. So I would expect average player to be below 1250 but gradually increase as I also increase my rating. And of course this takes into account that you always play opponents in your range. This doesn't work if you always play someone way higher of course.
Seriously, I haven't been on here long enough to realize this stuff about lower rated players...so I checked my stats and whatayaknow? My average opponent rating is ~150 points lower than mine! I'll have to change the default seek parameters; many of the people I've played haven't had a clue about this game (even less than me)!