That is yet another flawed analogy. The photons are reflected or emitted directly from the object. As opposed to its gravitational influence on some other object, where one is directly observing the *other* object, hence the inferred indirect detection of the first object.
I don't think you are understanding what I am saying.
Yes the photons are being "directly" emitted from the object, and the fact that we are observing not the thing itself, but the photons directly emitted from the thing is a layer of indirection. How directly something is observed is relative. It's not discrete, it's a spectrum.
As opposed to its gravitational influence on some other object, where one is directly observing the *other* object, hence the inferred indirect detection of the first object.
Yes it is *one more* layer of indirection. This doesn't mean we are not observing dark matter. It means we are observing dark matter in a more indirect way than we observe most other stuff in the cosmos (which we also observe indirectly).
"The existence and properties of dark matter are inferred from its gravitational effects on visible matter, on radiation, and on the large-scale structure of the universe. Dark matter has not been detected directly, making it one of the greatest mysteries in modern astrophysics."
As opposed to what? What properties of anything do we know about anything that are not inferred from their effects on other things?
Yes we don't know that much about dark matter. It's not because we can't observe it (which is what you originally claimed). Yes we can't observe it directly, I am not disagreeing with that. What I am saying is that we can't directly observe anything. Everything we observe is indirect, some more indirect than others.