I think we have an issue with what you expect for evidence.
Leave aside Gravitational waves, these are far from certain.
You're never going to get a photograph of a black-hole looking the way they appear in Sci-Fi films but you do get measurements of gas getting sucked in and then disappearing.
Here's an article on one such piece of work in 2001
http://science.nasa.gov/headlines/y2001/ast12j an_1.htm
Dark matter is interesting from a different perspective - there are a couple of good ideas out there, if one is right we may find that "dark matter" is all around us.
There is a difference between having a mind that is educated and open to one that just mindlessly considers every crackpot idea.
This one requires we reject over 100 years of work including the countless observations and data that support it.
And replace it with something that has no scientific basis in either experiment or theory