The point is people are already unconsciously putting themselves in buckets- being conscious of it is the first step towards actually moving past it. By being conscious of exactly how you are doing this, you can also begin to explore and accept the parts of yourself that don't fit into those buckets (what Carl Jung calls the shadow).
The "buckets" themselves (archetypes) are simply explaining different aspects of human experience and personalities, but absolutely nobody fits into them neatly, and they are limitless- you could probably come up with hundreds of them if you wanted to. Which you think are important and worth talking about is really a matter of opinion or personal values and goals.
These ideas are widely misunderstood and misused in both popular culture and the social sciences, but that isn't the fault of the concepts themselves. For example, the categories in the popular Myers–Briggs Type Indicator (MBTI) are from Carl Jung's archetypes, but people use them exactly like you said- to essentially justify their own behaviors, when the point is to explore the parts of yourself that are the opposite of that. This idea often horrifies people that are fans of MBTI and use it like you are implying.
I'm sure you would agree that people already have different personalities, and see themselves a certain way, and often dislike traits in themselves and others that are somewhat opposite traits to those. For example a person might see themselves as an analytical logical person, and look down on people who seem to be guided mostly by emotions. It can be hugely valuable for a person like this to start to understand and accept the emotional part of themselves and others, but that likely won't change the fact that they are still a person that prioritizes "thinking" over "feeling."
People often mistakenly call this Carl Jung stuff "pseudoscience" because they are misunderstanding it as trying to be science. It is not- it is a tool or technology for personal growth, and is not attempting to be a literal explanation for how the human brain works or anything like that. It would be more accurate to relate it to religious or spiritual practices like meditation.
The fact is that introverted people are quite rare compared to extroverted people, and extroverted people do tend to see it as a bad thing and want to do things like "help teach introverts to be less extroverted" but may be horrified by the idea of the opposite- learning about and accepting their own introverted aspects.