Well, honestly, I think it's good. Maybe if people got a choice to know or not to know, but I'm sure if they told the doctor not to tell them, they wouldn't.
If you know when the end is, it gives you opportunity to say goodbye, go through your bucket list, or other things. It lets you plan it out, at least. I mean, I'd hate to plan out going on a trip to Aus, let my friends get so hopeful, and then just die before I even got on the plane because I over-estimated myself xP And I'd hate to wallow away in a bed for the last few months of my life, thinking I'd die next week.
Doctors aren't trying to be cruel, they're trying to be fair. Don't be hateful because of that.
Besides, many people have made it long past what some doctor says they'll live for. It's only an estimate, it isn't complete fact. If someone loses hope, hate to say, it's their own choice.
(edited to change wording x0x)