"...is just a made up explanation for that. There is no evidence it exists."
The idea of dark matter is not that dark matter exists, it's that the dark matter theory is a placeholder used to explain the observations we see in the universe that are contrary to the physical understandings as we know them currently. The physicists are essentially saying there's a bunch of stuff we just can't explain, and dark matter is a concept that they refer to until we can finally figure out the bigger picture. It may be a while.
Japan has a single timezone for the whole country, for example
Same with Iceland.
The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!" (I found it!) but "That's funny ..." -- Isaac Asimov