why are we told to drink alot of water?

why is it considered healthy to drink lots of water? people should be drinking when they are thirsty, if you do not want more water you should not be drinking it. I found out that camels actually have fat in their backs, fat locks in moisture better than anything else natural. we need some water but many people think that you have to drink a specific amount like 2 liters. i do not think you should be forcing yourself to be drinking more than you want if you dont want two liters its not going to make you more healthy. I had mu suspicions on drinking more water not being a good thing but after doing some research it shows that the amount we are told is too much.