TL;DR, the questions asked were:

1. ‘National leaders should be selected by the people through free and competitive elections.’
2. ‘Individual rights and freedoms should NOT be infringed upon but be protected by the government.’
3. ‘Ordinary citizens should be allowed and be able to perform their civic duties such as vote and participate in public affairs at local and national levels.’

For each question, the respondents were asked how much they agree on a scale from 1 to 10, then the answers were added up (with combined total from 3 to 30) and then they were rescaled from 0 to 1 (with 3 → 0, 30 → 1).

For pre-1990 generations, the rescaled total was 0.83, for post-1990 generations it was 0.8. So, the way I look at it, support for those three values is relatively high overall, and has declined rather insignificantly.

TBH, I think the headline is pretty bad.

I don't think there's much "shunning" going on here. But also, I don't think the questions are necessarily about a "liberal" democracy. They had nothing to do with private property on the means of production, or otherwise capitalism, but rather about the style of democracy employed ("democratic dictatorship or proletariat" vs "representative democracy"). Given that the younger generations enjoyed the rapid growth and vast improvements in living conditions, it's no surprise to me that they also support the existing system more (even if slightly) than the older generations.