Companies use them because they're cheap, prevent microbe growth, and they aren't illegal. Twinkies use preservatives that can cause cancer and milk can contain hormones that can increase the age of puberty and likelyhood of cancer. Why do companies use those? They're cheap and legal.
These things are going to be legal until there are VERY FIRM conclusions made directly linking them to things. So what 9/10 breast tumors studied had parabens, were those women on birth control? Did they eat red meat? There need to be HUGE studies in order for things to be taken out of use, especially from cheap products..
There have only been a few small studies on parabens, but I'd rather not take the chance of introducing my body into any more cancer causing things than I have to, especially when there are tons of lubes out there that DON'T have them!