I'm guessing you're pretty young, late twenties at the latest.
I understand that I made a pretty broad statement, but anecdotally, there are so many different instances of boomers denigrating choices of later generations across many different buckets of choices - social, technological, moral, cultural, political, psycho-sexual; and as I've lived my life, we've seen rapid chances in societal behaviors that just make me feel that as every successive generation comes into existence, you just get that bit-flip for that dimension of the 'collective consciousness' (not woo-woo collective consciousness, but just the aggregated set of behaviors and interactions manifested by the people that exist today, that came to pass based on the pre-existing cc from their parents and those that influenced them, etc).
Psychologically, it's funny, because there is this commonly cited concept of 'teenage/adolescent rebellion' where, despite the love and adoration you feel for your parents, there develops a kind of rift in response to the rules imposed vs. what you immediately want to do/desire to explore the world without the parental control structure that was imposed previously. Perhaps the generational shifts that are seen are a consequence of this - maybe not, I'm just thinking out loud here. But yeah it is an interesting topic.
Care to comment further on what gave you this impression? I'm intrigued.
Try again for 1960.
Society has changed in the 60 years for sure, but not always in the way you predict, or the way you want.
The only thing that marks boomers as different is the technological leverage available to them. Meaning each and every succeeding generation since the industrial revolution can do more good and vastly more harm, than the one that went before. WW1 was so much worse than the Napoleonic war as technological leverage brought industrial slaughter. Similar comments were heard in Dickens day, in pre-WW1 Edwardian era, and I have no doubt will continue to be heard in 30 when it'll be the ageing Millennials being denigrated, and 300 years, etc.
Just to put your "only divisive because boomers" issues into context, ALL of them were divisive in the eras they were restricted, except the pendulum was swinging the other way. There were moral panics and outrages over all these in Elizabethan, Victorian, Edwardian times and still today. So that's 400 years. You'll find similar going back to ancient Rome and Greece.
We are going through a pendulum swing of relaxing attitudes to all of these, and decline of regulation. Regulation declines due to the rise of the cargo cult of neoliberalism 1980 on, attitudes due to the rise of individual consumerism 1960 on. Give it fifty or a hundred years and there will be a "universal" clamour for greater restriction, perhaps with a new spin, perhaps in forms of regulation commonly tried across the millennia. Perhaps religion or abstinence will see a revival. Perhaps something completely new, whether environmentalism or something we can't yet conceive.
At some point in the swing to relaxed, low regulation, rebelling against parents will necessarily spawn a more community, collective, or restrictive reaction.