Because the young people have the most at stake.
They will be sent to war
They will foot the bill
They will live in tyranny
The older generations will have sucked the lifeblood what remains, and then die off leaving the younger generations to clean up the mess.
Thats a broad brush stroke, but its worth noting that there are many in the older generations who feel it is their responsibility to correct things. Still, I'm afraid, that there are the majority in certain age groups who only care about themselves.
You cant really blame them, its human nature. But it definitely speaks against bigger government, which has been the catalyst of nearly all our problems.
So again, the government made promises to the older generations, and those generations want the government to deliver. The older folks get frightened of any perceived cut in benefits - Our challenge is to convey the reality to these people. Ron Paul is the only candidate who can secure your entitlements.