Think of it this way: if 10% of every other generation does X, but 40% of a particular generation does X, then that generation really should be known for doing X, even though the majority of members of that generation don't do X! Don't let the easy availability of anecdotal counterexamples to a trend fool you; a trend in a population is a trend even if not literally everyone in that population is a part of it.
Of course, there might well be a better way to divide up the population that serves as a better predictor for the trend, and so "explains away" the generational effect. E.g. changes in racial composition (and so culture) due to immigration over the years; or growth of subcultures as self-reinforcing memetic entities, apart from any generational proclivity toward them; or economic effects pushing people to have different emotional needs (e.g. a change in gender-balance of the workforce will see different types of businesses created to offer self-care to tired workers.)
But, by another lens, all these other effects are "part of" the generational effect; they're the composition of the narrative the generation will tell about itself, and so be remembered for.
I was born in a year that traditionally was generally not considered "millennial" by demographers, but since it also did not fit with the years they used for previous generations, modern definitions tend to include my birth year as "millennial". This irritates me, because myself and most of those that I know who are my age don't fit the usual descriptions of "millennials" and we don't like the association. Now, I happen to like millennials. My wife is solidly in the millennial years. I have many friends who were born in the millennial years. But I don't like having the label applied to myself and I don't fit the descriptions at all.
In the end it isn't a big deal. I have no plans to ever call myself a millennial. But it is worth cautioning against stereotyping individuals because of the year they were born, as I unfortunately see many people do.
It's definitely some level of stereotyping, but there definitely appears to be a divide with friends (especially from college) who are a few years older than me, and those who are a few years younger. The older group finished college and entered the work force just as the internet was really beginning to churn, when it was interesting but not necessary, when it was still easy to ignore the digital world socially and economically. As a result they seem to be much less plugged in online than my friends who are just a few years younger.
You sound like you were born in 1981 or 1982. I noticed this phenomenon as well, and it led me to conclude that "millennial" (and, to be fair, most other generational labels) really functions in common usage as an epithet, ie. anyone younger (or older) than me that I wish to denigrate by stereotyping them.
It's normal you don't associate personaly with every trend. Especially if you lived in some local bubble or if you are on the edge of some defined group. That doesn't matter and I would just ignore it. This isn't about any specific person.
Being out of step with your peers is a separate issue.
What kind of research? Can you give references?
If you mix 50/50 red & blue, obviously that's purple.
When it's 80/20 red & blue, that looks more red than blue but looks purple but not the same as above.
When it's 20/80 red & blue, that looks more blue than red but looks purple but not the same as above.
It's a classification using a gradient, not an integer so yes, the boundaries are hard to tell but are still there.
Sometimes there genuinely are very big changes between generations. E.g. Brexit, which is much more widely supported by old people than young people.
Gen z were/are young adults during the '10s. Gen alpha will be young adults during the '20s.
Generally a person's pre-teen/teen/early 20's are very formative so the shared experiences that a generation will have probably do form a real connective tissue within the age cohort that separates them from those with different experiences. A binary (anyone less than x years old is a y) isn't so useful to describe such a phenomenon.
1982 - 1996, that is more than ten years. But the people in that range would have shared formative experiences during the '00s. Thus the moniker millenials.