The Left’s hatred of the older folks is rooted in the Orwellian desire to forget everything that happened, was believed, and was considered normal until 5 seconds ago. This is supposed to make the insane ideas they peddle more palatable.
In the USSR, this raging contempt towards older people was also a big thing. Young people were very easy to bamboozle into hounding the designated enemies. Plus, they could dedicate a ton of energy to this activity.