Why do people answer questions with "I don't know" on here?

Question

i am ready for many sarcastic responses. i.e "i don't know"

Answer 1

For the points.

Answer 2

Just for the 2 points

Answer 3

I don't know.

(Sorry)

Answer 4

2 points for every answer!  

Answer 5

for the 2 points??

Answer 6

i dont like when they do that either

they only want the 2 points

cp

Answer 7

Because they are so desperate to get points that are useful for so many things!