Some historical periods are more defined than others, and produce a more clearly-delineated cohort. The Baby Boomers, those born roughly between 1946 and 1964, are one such. I would adjust the starting date, as I know one classic Boomer born a few years earlier; the crucial thing seems to be – did they grow up, or experience their early adulthood in the West during the 1960/70s? If so, Boomer.
They share certain characteristics:
1. They typically either have no children, or left their children to fend for themselves. They were themselves taught basic life skills (how to cook, change a tire, etc.) by their parents, but assume their children will just absorb this knowledge without effort on their part; far from acknowledging his/her parenting failure, the Boomer will blame the children for having no idea of how to maintain a car.
2. They effortlessly found work after leaving school, and think that a university degree is a passport to a 6-figure salary.
3. They not only own their own homes, they were able to pay the mortgage off within 5 years.
4. They believe everything they read in a newspaper, everything they hear on the radio, everything on TV. It is impossible to convince a Boomer that mainstream media is mostly propaganda. Even if a Boomer can be dissuaded from one mainstream media site, they will immediately find another in which to repose their blind faith.
5. They are obsessed with Nazis and Jews. For the Boomer, Adolf Hitler represents all that is evil, and thus Jews and Israel represent all that is good. For the Boomer, the worst possible insults are: anti-semitic, racist, Nazi.
Boomers demonstrate classic r-selected behaviour. According to r/k life strategy theory, r-selected creatures (e.g. rabbits) develop in a resource-abundant but unpredictable environment, where grass is ample but a predator could appear at any moment; k-selected (e.g. wolves) develop in a resource-scarce but stable environment. r-selected creatures are basically hippies: conflict avoidant; bearing no loyalty to their group; fucking everything that moves and investing no energy in their offspring. Rabbits are the hippies of the animal kingdom.
For Boomers, the crucial factor is resource availability. The Boomers grew up post-war, and even if they went through 1950s rationing, they were young enough to be formed by the degenerate “anything goes” 60s.

“Make love not money” only works in an affluent society, with no risk of starvation. As a slogan it could only have arisen in an environment of not merely abundant, but easily-obtained resources. Free love means you don’t have to exert any effort to get it; and that it has no value.
I know several Boomers who drifted for years, somehow surviving without a job, and then effortlessly got work as journalists, academics, etc. – work for which you now require a PhD and a decade’s unpaid experience.
One need only compare those born between the 40s and mid-60s in the West, with Eastern Europeans, to see the difference – it is a question of resource availability, the Westerners being Boomers Supreme, the Eastern Europeans hard-bitten turnip-eaters.
The Boomers were conditioned, by abundant resources, to behave like rabbits: feckless, selfish, open to other cultures, unable to understand basic loyalty, unable to value their own family, let alone their culture or nation or race.
Boomers grew up after World War 2, and so their founding myth was that of the Holocaust. Where other cultures trace their origins back to a god man or a heroic war, since 1945 those who arbiter society have insistently pushed the Holocaust as the central axis of the West: so George Steiner often wrote of pre-1939 literature as clackety-clacking on the train tracks to Auschwitz, and of course everything thereafter must be forever an anguished lament for the holy six gorillion. For the Boomer, the worst thing that could ever have happened is the Holocaust, and the Boomer’s parents either took part (if German) or fought heroically against it; the Boomer, alas, was born too late to take part in either gassing Jews or shooting Nazis, and so grew up feeling both privileged (rabbits in evergreen meadows) and as it were culturally posthumous; the only thing left for the Boomer was to create a new reality, based on opposition not merely to the Holocaust but to everything that could be construed as Holocaust-lite: nationalism (except for Zionism, of course), Christianity, especially Catholicism; Germans; European history; Europe; white people; even the very mildest anti-semitism (to the point that some Jews are accused of being “self-hating Jews” because they don’t fully subscribe to the narrative).
Thus the tiresome self-aggrandizement of the Boomer, bellowing about their pet topics. There are plenty of exceptions but in general those who grew up, in the West, in the affluent 60s and 70s, were forever ruined by their environment, their myth.