That's not exactly what I was talking.
1) Modern Warfare 2 use DRM under Steam, not SecuROM and SecuROM is very common in hard copy games that don't require 3rd party apps, such as Steam to be installed. Some PC gamers don't want any games to be integrate with Steam for some reason due some games may require online but only problem about if you are playing games on road and try to play games under Steam but won't run due no online or have wait to find WiFi hotspot to connect it, also other reason are personal.
2) Modern Warfare 2 isn't only game that require Steam to play so same goes with Saints Row 2, Left 4 Dead and rest of games that published by Valve so you are require to have Steam to play, that what some PC gamers don't want for personal reason, along with no dedicated servers and no mods, that what many CoD PC fans are very upset about traditional has taken away.
There's list of games that use SecuROM, Modern Warfare 2 isn't on list because they use Steam DRM, unlike previous CoD, both of Modern Warfare and World at War use safedisc (confirmed) so no need to run Steam.
Know Your Game! Tiki : List of games with SecuROM 7
If you don't see any games on list so games are probably protected by Safedisc, Steam, Impulse, Star Force, Tages or no protection, The Sims 3 is protected by EA copy protection due many Sims fans hate SecuROM and Far Cry 2 has no protection after Ubisoft issue an patch to remove it after many complaint like many recent games from Ubisoft.
3) They cannot use SecuROM and Steam in combined because it does cause conflict when you are try to back up the game so EA made mistake and issue an patch to remove the SecuROM but left protected under Steam DRM.
The games with Steam DRM is still cracked, there's alot of Modern Warfare 2 on torrent and some hackers made new installation for Modern Warfare 2 to run without need use Steam.
4) I had researched alot about copy protection and I'm against on DRM, that why I'm encourage pirate to buy legal copy or send money to game developers if they love their game, even some people rather to use torrent to download the full version of game because demo isn't enough.
Activision does make alot of profit so far than losing the profit because you cannot play in multiplayer with pirated CoD games, it was Infinity Ward decision to use steamwork for games so Activision accept it so I'm blaming on IW instead of Activision.
I'm wait to get Battlefield Bad Company 2 for PC and it will support dedicated servers and mods.
Direct2Drive and Gamers Gate use game's own copy protection, such as SecuROM, Safedisc, Tages or even no DRM on some games because they use first party installation.