Sometimes we like to discredit things, and we frame our discrediting with clear indicative phrases like "that's just...", "nothing more than...", "all that is...", etc.
Often, these indicative phrases not only indicate an ensuing discredit statement, but also indicate a massive over-simplification.
An easy example is basketball: "That's just people putting a leather ball through an iron hoop."
No. No it isn't. Basketball is significantly more complex than that, it has rules, strategies, actions, leagues, organizations, endorsement deals, scholarships, etc., all of which are left out of the above appraisal.
That phenomenon, basketball, hasn't remotely been discredited, because it hasn't remotely been described.
Has anything been discredited? I'm tempted to say the speaker, but that is yet another oversimplification. The statement simply discredits itself.
What's frustrating about this kind of maneuver is it's ubiquity--anything can be incompletely described in such a way.
Am I currently writing a blog post, or am I "just" touching the screen of my phone over and over?
I am touching the screen of my phone over and over, but (hopefully) it's evident that more than that is going on.
Is reading a book "just" looking at ink and paper?
Is building a house "just" swinging a hammer at some wood?
Is a family reunion "just" a bunch of people in the same place?
You get the idea. I hope.
I think the reason we do this is to try to fortify subjective preferences with "objective" reasoning. We like our opinions, and we'd like other people to share them. But, there's really no reason why they should. Opinions are things we like, things we don't like, personal tastes, and so on. They are not facts. Facts are features of the world, which we all share in common. Fail to deal with them, and you are, in a very important sense, ignoring the world. Opinions are features of our own individual mental landscapes, which no one else shares in common. Why should anyone else have to deal with them?
So if we could give factual reasons to support mere opinions, our opinions take on an external authority that we, as well as our peers, must bow to.
But we can't give factual reasons to support opinions. We can explain them using facts : "I was forced to listen to this song as a child while my parents stole my money." But that's hardly the same thing.
It doesn't make sense to say opinions are "better" or "worse", they are just different. Oversimplification is one way of attempting to make an opinion appear "better", but as we have seen, it fails.
More than that, it shuts the door to other experiential possibilities: if we write categories of human endeavor wholesale (no matter what the reason might be) we, ipso facto, preventing ourselves from experiencing them. That's fine sometimes, when there are good reasons. I'd very much like to preclude myself from being involved in a murder. Ending a life causes suffering.
However, if I preclude myself from experiencing jazz because it's "just a lot of chaotic noise", I might be preventing myself from having an experience of something I later find out I really enjoy.
On the other hand, if I'm honest and say something like, "I just can't get into it, it's not for me." I've kept my comments about my own subjective states, and haven't implied that the jazz musician sitting next to me is completely wasting his time.