...in not being clear enough with what I mean. Both can be explained in the context of current theories only if you make some assumptions, like the existence of dark matter or dark energy. But then, almost anything can be explained if you make enough assumptions (i.e. any law of gravity will work if you have freedom in choosing your matter distribution). Until we observe these things or have some justification for their existence, I will remain skeptical about the current explanation. That's not to say that I dismiss it, I just think it's one area of physics that leave open the possibility for a new theory.

This is dramatically different from the areas Ray is talking about, such as nuclear physics and weak-field GR. These are both on a firm theoretical and observational foundation, at least in the regimes that we have so far explored. The somewhat more mathematically inclined crackpots usually go after the things that are still shaky, like dark matter and dark energy.