Not that I agree with it.
The term "millennials" was coined before "Generation Y," and the initial definition was children born during or after 1982, which is more or less where it stands now (I've seen the definition of millennials get extended back to 1980, but rarely if ever into the 70's.) Generation X is actually the one that absorbed the originally defined Generation Y, which comprised children born from 1974-1980.
Citation: https://en.wikipedia.org/wiki/Millennials#Terminology_and_et...
So a 51 year old is most definitely Gen X and not a Boomer. No matter what. Kids born in the mid-70's (50+) are quite outside by more than a decade of the baby boom period.
Source: My parents are definitely boomers, and I am definitely GenX. I'll leave it as an exercise to the reader to learn what the X meant. It was significant in the same way "boomer" was. Anyone trying to change or extend the meanings needs a history lesson.
Baby Boomers, GenX and Millenials all have meanings of significance to their titles, whereas Y, Z and the super weird "alpha" are just keeping up a pattern that loses the meanings of the other generations that got meaningful names.
My 6th grade teacher (in the early 80's) asked our class once which of us thought that the world would end in nuclear armageddon, and all of us raised our hands. I mention this as it's likely a baseline for how Gen X'ers view the state of the world.
