It's common sense I think. Public opinion across all age groups is in favor of SS, so even without any other information what I said is true.
Apparently, logic is not your strong suit. In order to make a valid claim that most young people are in favor of Social Security, you would have to present a sample exclusively made up of young and then polling them for their support/opposition to Social Security. Instead, you have made a blanket statement of all people and then applied that statement exclusively to young people with zero evidence of support. So no, there is no deductive way to claim your statement as "true".
Young people want social security.
Apparently, math isn't your strong suit either. Consider a worker earning $25K/yr ($12/hr). Beginning at age 25, this worker is allowed to take the portion of his income earmarked for Social Security taxes and invest that money in a fund averaging 7% growth. He does this for 40 years earning the same $25K and investing the same amount each month.
When he retires at age 65, he will have a retirement fund of over $680,000. The interest alone on that will net him a retirement salary of $47K - almost double what he made as a worker. And he won't even have to touch the $680K. That will remain intact until he dies, at which point it would pass to his children and grandchildren.
Given this option, you seriously think a young worker would prefer giving his money over to the government instead (to be spent immediately) with some promise that he will get a check from them until he dies at which point his children and grandchildren will be given a whopping $255 check? Think, man.
Also young people today are more left leaning than any other generation.
Young people today are more cynical and apolitical than any other generation., thanks to broken government promises. And they are already pissed off that the government has screwed them over bigtime on student loans with interest rates 3 times the discount rate.