The reason to think that the hot gas emitting x-rays didn't collide with the cooler individual galaxies is that's what the evidence shows.



How coincidental that the combination of all of those miscellaneous factors just happened to create exactly the same effect that we would predict from dark matter.



I really don't understand this perception that scientists are over-eager to "tell a story" that isn't well-supported by the evidence. One of the best ways for a scientist to contribute to the field and make a name for himself or herself is to disprove or supplant an existing theory, and every scientist knows this.

The sense that I'm getting is that you have a preconceived opinion about dark matter, and in order to hold on to that, you are willing both to interpret evidence in a highly selective manner and to believe yourself actually more qualified to analyze this issue than hundreds if not thousands of trained, educated, experienced scientists. Have you taken any classes or done any independent study in astrophysics, general relativity, cosmology, etc.? These topics require an understanding of gravitation, thermodynamics, electromagnetism, nuclear physics, optics, and that's just for starters.

The existence of dark matter is not currently a matter of scientific controversy, despite whatever impression the media gives in order to create better news stories. Skepticism is important, but skepticism in the face of evidence is not a virtue. On the off chance that dark matter doesn't exist, rest assured that people will figure that out.