Again, the problem with this kind of polling data is if they only release the percentages you can't know just how many 'Young People' have taken part in this poll, it's the same tactic used in other political polling where they say a percentage of 'Americans' believe and then when you look closer it reveals there has only been a 3000 poll sample which obviously is nowhere near an accurate representation of an entire country.
Data like this is horribly unreliable and should never be trusted, if you've got a bigger polling sample than say 5000 then there might be a point to it, but otherwise it's just political groups trying to trick people into thinking the world is against people who disagree.
That was on page 2 of the link I posted went to source but I'll put a bit of it here as well
http://www.people-press.org/2015/01/22/most-view-the-cdc-favorably-vas-image-slips/2/About the Survey
The analysis in this report is based on telephone interviews conducted January 7-11, 2015 among a national sample of 1,504 adults, 18 years of age or older, living in all 50 U.S. states and the District of Columbia (528 respondents were interviewed on a landline telephone, and 976 were interviewed on a cell phone, including 563 who had no landline telephone). The survey was conducted by interviewers at Princeton Data Source under the direction of Princeton Survey Research Associates International. A combination of landline and cell phone random digit dial samples were used; both samples were provided by Survey Sampling International. Interviews were conducted in English and Spanish. Respondents in the landline sample were selected by randomly asking for the youngest adult male or female who is now at home. Interviews in the cell sample were conducted with the person who answered the phone, if that person was an adult 18 years of age or older. For detailed information about our survey methodology, see
http://people-press.org/methodology/The following table shows the unweighted sample sizes and the error attributable to sampling that would be expected at the 95% level of confidence for different groups in the survey:
Sample sizes and sampling errors for other subgroups are available upon request.
In addition to sampling error, one should bear in mind that question wording and practical difficulties in conducting surveys can introduce error or bias into the findings of opinion polls.