It appears that you don't know how historically dark matter theory came to be.
Actually I would argue that the reverse is true because I'm old enough to remember when the term "dark matter" didn't necessarily imply exotic forms of matter. I think it was Fritz Zwicky who first coined the term. Originally it didn't automatically imply an exotic type of matter however.
At first, astronomers and cosmologists did assume that baryonic matter is all that there is.
Sure, and they do in fact have observations and "galaxy mass estimations" that don't seem to jive. That conflict between observation and baryonic mass estimation could be related to almost anything, including errors in our baryonic mass estimates, which is likely considering the revelations of the past decade.
A few observations (in 1930-40) which claimed to maybe detect discrepancies, were ignored - which is ok, since there are _always_ some observations which find "something strange", but these may well be instrument errors or mistaken interpretation or logic of their authors.
Then Vera Rubin in 1970s worked on galaxy rotation curves and found that galaxies seem to be heavier than they should be. Her work was high-quality and was checked by other independent measurements, but still, science did not jump on dark matter bandwagon overnight. The status shifted to "hmmm, there is indeed something fishy here! Let's look at it more carefully!"
The entire 1980s were spent doing more observations, looking at several disjoing pieces of evidence, and all of them pointed quite consistently to the conclusion that baryonic mass alone is far from being enough to explain them.
Somewhere between the early 70's and 2006 the term however gradually "morphed" from being synonymous with "we don't know what that missing mass is made of", to being associated with an exotic type of matter. I don't have any doubt that there is evidence of 'missing mass' from galaxy mass estimation techniques, but I have no evidence to suggest that any of that missing mass is to be found in exotic types of matter, and in fact I have no laboratory evidence that exotic forms of matter even exist in nature.
Since you don't remember this long and convoluted process of history, you seem to assume everybody just happily fudges their models and observations to satisfy their preconceived notion that "dark matter exists"?
I think you misunderstand my position. I have no doubt that there is a 'missing mass' problem which could be related to just about anything, including serious mass estimation problems with our galaxy mass estimation models. There does seem to be *ample* evidence that we've simply been underestimating the amount of ordinary plasma that is present in various galaxies. We didn't even know about the existence of that hot plasma halo, or that cooler hydrogen halo around our own galaxy until quite recently in fact.