Actually they are quite easy to take down (If your smart)
While it's
possible to defeat a player using hacks, it's
not at all easy.
What if you're smart... but don't have the supplies necessary to do it? Maybe it's still near the beginning of the game, and you only have ten arrows and no FNS.
Also, you're assuming that the hackers rely
solely on their hacks to win. You're forgetting that hackers are usually
competitive and also have strategies. Many of them start out playing normally, develop skills and strategies, and then give up and turn to hacks. Some of them are still good without their hack clients.
You think you can shoot them down? They can shoot you down, too!
FNS? They can dodge it and light you on fire, as well!
I've been around for two years, and have fought what is probably
hundreds of hackers. I'm
also considered one of MCGamer's smartest players
(i have bragging rights from the MCGamer Awards :3 I need to use them before they expire) and I still die quite often. Heck, I'm sure even Darkrai and Gravey4rd die to hackers, even though they're considered some of the top PvPers in all of Minecraftia!
(Is Minecraftia even a term anymore?)