> Having dark matter particle(s) is also not that strange. As far as we know there's no requirement that a particle interacts with any of the known forces beyond gravity.

This is the key thing. As we still don't have a theory of everything, which explains the fundamental reasons why every particle is the way it is, dark matter is a very straightforward and simple explanation.

The name makes it sound stranger than it is. It's just particles that have mass and are affected normally by gravity, but which are unaffected by the electromagnetic force.

It's not a particularly exotic or implausible or wild idea. In fact it's so simple it's almost boring. It's just obviously inherently difficult to test directly, since gravity is such a weak force.