Frovingslosh is saying dark matter doesn't exist. He's wrong.
That's a very strong statement. I personally would say no more than "Something we don't fully understand is causing an effect".
Our statements are almost identical. The term "dark matter" is just shorthand for "something we don't understand, exerting a gravitational effect". There's also the possibility that there is no "something" and our understanding of gravity is wrong, but that has now been all but ruled out.
You spend 8 billion to get 100 million worth of R&D it's not a great use of funds.
This is a separate argument, but I'll answer it with two important points:
1. You can't put a value on fundamental research. The Higgs Boson in unlikely to have any direct application in the near future, but what about superconductors, or RF generators, or ion sources, or ultra-high vacuum techniques? All technologies which have been heavily developed for particle physics, and which have already found their way into industry. Even if you came up with a figure for the value of those technologies up to now, there's no way you can measure their future value. Yet future progress without them is unthinkable. All our technology is built on fundamental research, so if technology (and by extension, civilisation) is to advance so must fundamental research.
2. Could you develop the same technology more cheaply, without building huge science experiments? No. Of course not. Who would spend their whole career perfecting some obscure device if there wasn't a chance of participating in a great discovery? Industry just can't generate that kind of motivation.