From the wording of this article it sounds like it’s explicitly talking about missing non-dark matter, which is separate from dark matter. So it wouldn’t ‘confirm’ your opinion.

I'm pretty sure 'dark matter' candidates do include cold baryonic matter, it's just that in large part it's been ruled out due to a lack of observations exactly like the one reported here. The fact that we had not seen it, until now, did not definitely exclude it from the definition of dark matter; it just made it rather unlikely. In the absence of observational evidence, alternative, more exotic theories were developed.

The interesting question is how did this cloud form? One of the reasons, for example, that 'dark matter' can't be cold dead stars is that even if the stars were formed at the dawn of the universe, their remnants would still be warmer than the background temperature of the universe and thus we should be able to see them. Many other 'regular' baryonic sources were ruled out for similar arguments, eg, any process that could have created them would have imparted sufficient energy that we should be able to see it, or it would have been swept up into a star or formed a new star. The article did propose a mechanism, but I wish it went into it in more depth. Figuring out ways to explain the observation could lead to insights we had previously overlooked.

Most scientists also thought it was crazy at first--surely there must be some simpler explanation than just conjuring up a new type of matter. But at this point, the dark matter theory is by far the most popular.

There are a lot of reasons we know that dark matter is (almost certainly) non-baryonic. For one, we know how much baryonic matter there is (based on models of the big bang, etc.) And while no one has seen dark matter in a laboratory, we have observed it indirectly (eg by gravitational lensing).

[1] https://www.nasa.gov/vision/universe/starsgalaxies/dark_matt...

I did a thought experiment once about wormholes, and how gravity would pass through them creating quite a messy curvature of space (potentially dangerously so near a planet or sun).

Don’t we think wormholes would look like gravitational lensing?