Because stuff like the Bullet Cluster exists. Dark matter is in fact the simplest answer.

https://en.wikipedia.org/wiki/Bullet_Cluster

I feel compelled to point out that (a)ether was the simplest answer until we confirmed that space is a vacuum and that light can travel in the absence of a medium.

Abandoning aether was NOT a "simple" answer. One you abandon aether, all manner of weirdness suddenly pops in.

Light being the same speed irrespective of observer is weird. Velocity dilating length and time is weird. Not having a preferential observation point is weird. Not needing a medium for transmission is weird. Not being able to agree on simultaneity is weird. etc.

Aether wasn't just something that a bunch of dullards clung to. You have to abandon some very long held common-sense understanding when you give it up.

That's my point exactly.

aether was not the simplest explanation since it was disproved by Michelson-Morley experiment. Nothing as of now yet has disproved Dark matter as thoroughly.

The two were dealt with very differently.

Aether: observations show lack of aether so we update the theory that makes aether unnecessary.

Dark matter: observations show lack of observable matter so we keep hunting for decades locating it. The aether analogue would have been to continue to look for dark aether. Dark matter is more like god of gaps. We can 'darkify' any theory that does not fit empirical evidence.

It's hard to tell now which leans more towards the more correct theory.

Angry gods used to be the simplest answer for a lot of things. Inevitably we find a better model

You are of course very welcome to propose this supposed better model, but please do some due diligence and learn to roughly understand the current flawed models firsts.

For example "angry gods" was never a simple theory, one needs only to read some fan fiction to understand that theology gets complicated fast. Instead "angry gods" is a simplified summary of a very complicated theory about metaphysical hierarchy, creation, agency, the meaning of divinity, and cause and effect, etc etc.

Simplest in this sense does also imply predictability for Dark matter, which cannot be said for angry gods. Angry gods is anything but a simple theory.