This was a categorical statement about 20-somethings and as such isn't ad hominem. I would still say that if their advice was just as eloquently stated opposite.
>>varjag+(OP)
My Latin is rusty, then it is perhaps "ad populum", attacking the people. In any case, you're not addressing the message.
"Ceterus paribus" yes, older people are more wise due to experience, but I have met 28 year olds which are much wiser than millions of old, insular, dumb 50-80 year olds.
>>unethi+sj
Sometimes you have to address the merits of large groups of people however, no other way doing that. "Childless advice on parenting is dubious" in the sister comment for example. And come on, every one of us was in their 20s some time.