In Counter-Strike's new version, 1.6, several new weapons were added. The Terrorists received the Galil, the Counter-Terrorists the Famas and the Riot Shield. In addition, some weapons were tweaked; the Desert Eagle, though still ridiculously powerful, is not as powerful. Likewise, the previously nigh-useless autosniper rifles were made more accurate, which means they're actually worth the exhorbitant price you have to pay for them.
Of the various tweaks and new weapons, by far the most controversial is the Riot Shield. This is because you simply cannot shoot through it (which, you have to admit, is kind of the point). Even the fearsome AWP, the terrible sound of which resonates through an entire map every time it is fired, cannot penetrate the Shield. Naturally, this annoys the AWP Whore somewhat; here he's spent $5000 dollars on this beautiful phallic symbol ridiculously overpowered rifle, and here some n00bish CT who only spent $2000 can just sit behind it, typing out insults to said AWP Whore's mother's sexual habits. Hence, the AWPer calls him a "Shield Whore." On the insult food chain, Shield Whore is fast replacing AWP Whore; I can AWP for almost 10 rounds straight before someone calls me an AWP Whore now, but woe be unto me if I dare even pick up a Riot Shield off of a dead CT, let alone buy one.
You might think I'd empathize with the AWP Whore, that I too am one of the ranks of Shield Haters who constantly bitch to Valve to remove it, but I don't. Why? Because the Shield, frankly, is not that great a weapon. First, it takes up your Primary Weapon slot. That means no m4a1, no AK-47, and most definitely no AWP. This means you're left with pistols: The Glock 18, the USP, the Desert Eagle, the FiveseveN, and the PPK (you can't use the Dualies with the Shield, naturally). (Since nobody ever buys a pistol besides the Desert Eagle, that's pretty much what you're guaranteed to see when you go up against a Shielder.)
So here you are, toting this heavy Shield which slows you down even more than an AWP, and all you can do is hunker down behind your shield, hope the enemy is stupid and does what most people in Counter-Strike do: empty an entire magazine into the shield, which does absolutely nothing. Forced to reload, this is now your opportunity to move the shield aside and nail him in the head with your deagle. This is not a very good strategy because it only works on one person. If two enemies come up to you and one of them has the brains of a soft-shelled turtle, one will sit there and fire at you while the other will calmly walk around behind you and stab you in the back of the head.
That being said, the Shield can work if you know what you're doing and don't try to charge in and massacre the entire opposing side by yourself. Counter-Strike is, after all, a teamplay mod. The Shield has a variety of such uses that, while not exactly a friend to your all-important killscore, will lead your team to victory; for example, crouching in an open area behind your shield, giving your teammates a shelter from which they can reload or even snipe at the enemy. That is the idea of the Shield, not to become an invincible terrorist-killing death machine (we have god mode for that).
Overall, the fact is that even one-on-one an intelligent terrorist will almost always pwn a Shielder. This leads me to conclude that people who endlessly call Shielders "Shield Whores" should STFU, because the Shield is generally not used intelligently enough for it to be true whoring. You don't have to be intelligent to be an AWP Whore, but to be successful with a Shield you really have to know what you're doing. People who buy a shield and crouch in a corner are not Shield Whores. They're stupid.