But dark matter is theorized to he a particle that we haven't observed yet, which sounds like "matter" to me. The specific idea to fix up the discrepancies is, there are huge clouds of invisible particles. There are competing theories on what sort of particle they might be, but dark matter theories predict that these particles are out there.

again, thats what theoretical physicists do. Someone makes a weird observation and your theory is left with a hole. You try to plug it.

They don't preach these things. Physicists don't run around preaching unprovable holy grail theories. They just make something up. Out of nothing. Because its their job. They need to come up with falsifiable theories that can be verified in lab experiments.

In order to do so, they HAVE TO hypothesize something. They can't just say "err dark matter right?". They have to say "there could be a particle with these properties, a mass of roughly X, producing a cross-section of Y when bombarded with tau-leptons etc.". That's just the scientific method.

Any physicist who postulates particles does that from a position of "it probably doesn't exist". The same way when you measure something to be faster than the speed of light, you assume that a cable is broken.

Then some journalist comes around saying "lol paper says weird particle exists, scientists are whack". That's annoying. But it happens.

If journalists wrote about CS the way they write about physics, the next time someone loses 2 BTC from their wallet, they'd claim that thats hard evidence of quantum computers being invented by north korea. Hypothetically plausible but as outlandish as permissible by reality.

Dark matter isn't theorized to necessassrilly be a particle either (finding new symmetries in the standard model would be extremely surprising)- it's literally just a placeholder name for a massive (as in, exhibits mass) unknown.

Dark matter theories absolutely do theorize invisible mass-bearing particles.

https://en.wikipedia.org/wiki/Dark_matter#Composition_of_dar...

It might be ordinary matter hidden from us somehow (maybe inside black holes) or something new like sterile neutrinos or WIMPs.

Yes, one way to restate my post is that dark matter could or could not be a new particle. The important part is that dark matter proponents assert there is something(s) whose mass we can detect, but whose other properties we can't measure as it doesn't fit into our current physical models.