People like categorizing things, so I can definitely see the merit. I does, however, get complicated when you try to categorize people.
What tends to be forgotten is that the main factor of these generation labels is very much just years. Anything else included just leads to errors. There's way too much in terms of life circumstances, sickness, shifts in society, etc. that can only vaguely be grasped. So what it end up being is people make a lot of assumptions.
People who make these assumptions are usually those of older generations. As for what they are concerned, they only see the system they created and they consider "working". So when a new generation comes around being all about "but this doesn't work", they see that as an attack to all they built up ("attack to working system=trying to destroy society"). Additionally any generation tends to have a very vocal minority who are extra loud and it's easy to associate an entire generation with just that minority (part of human psychiology is that they perceive the negative a lot more intensely than the positive).
As being part of the Millenial generation, due to living circumstances, a lot of the "attributes" people associate to the group don't really fit to who I am. At the same time, there are also a lot of them that do fit. I'd say it about evens out.
At the same time, I still find myself having trouble to understand which generation is which at times, which is why I try to avoid using the labels for the most part.