Boomers hate millennials. WWII generation hated Boomers. The WWI generation hated the WWII generation. There is a quote from Aristotle about how terrible young people are today:
"They [Young People] have exalted notions, because they have not been humbled by life or learned its necessary limitations; moreover, their hopeful disposition makes them think themselves equal to great things — and that means having exalted notions. They would always rather do noble deeds than useful ones: Their lives are regulated more by moral feeling than by reasoning — all their mistakes are in the direction of doing things excessively and vehemently. They overdo everything — they love too much, hate too much, and the same with everything else."
Millennials aren't any different from any other generation. There are good ones and bad ones and the older ones don't like them. When millennials hit 50 they'll complain about "kids today" too.