Why are there so many trolls on Yahoo answers?

Not enough users reporting them.

because it's very easy to be a troll when you are anonimous and no one can identify you

Because Yahoo keeps giving them all the powers they need, and zero protections to the level 7 users.

They gave trolls, Anonymous, the power to move questions........ reporting was not working for months........they allow KNOWN TROLLS, oft suspended, to create 20 accounts at once........and it all allowed the trolls to multiply like rabbits here.

I've gotten my stalker suspended over a dozen times, and he still has a dozen active accounts.

Because they were run out from under bridges by the homeless.

Pure boredom, though some are actually funny to read.

they have zero lives including they love making our lives crazy. which my turn my category and if they not careful i am going to sue everyone one of them and yahoo if yahoo does not do anything about them

They're atheists. Not a very mature group of people. Yahoo does not really regulate anything. They allow people to behave however.

Boredom.

I guess a lot of people are Bored and have nothing Better to do

The elves too