The more exotic a position is and the less direct evidence it has the more skeptical I am, but as it becomes more familiar, particular if that's due to mounting evidence, my skepticism proportionately decreases. If dark matter is "simply" matter affected by gravity as well as the weak and strong nuclear forces but not electromagnetism that's not so controversial since, as you note, neutrinos are already known to do that, and black holes effectively ignore everything but gravity as well. The idea of some radically new kind of matter bound by few if any of the known rules apply (which is the impression I, rightly or wrongly, often get in discussions of dark matter) is more of a hard sell for me.

Not ENTIRELY different; they're both cosmological issues. Large undetected mass might explain apparent acceleration in much the way it's thought to explain the Bullet Cluster--but doesn't. Dark energy doesn't seem to have much definition beyond being a placeholder for the actual explanation, and the characteristics required of it to provide that explanation. While I certainly support hypothesizing I also think it important to guard against fitting data to the curve rather than the reverse. Again, I don't claim to be an expert on cosmology or particle physics, but the little my amateur interest has shown me suggests that may be more common than anyone would like to admit.

Maybe so; the research I've done isn't extensive, no.

Sometimes it feels like physics and the profession of physics are two different things, or at least only somewhat related. For example, the flip side of what you just said is that if neutrinos are dark matter then dark matter hasn't been a new concept needing evidence amounting to proof since the first neutrino was detected. Of course, looking for more relatives of the neutrino isn't quite as sexy (and grantworthy) as looking for mysterious theoretical dark matter that literally changes the whole universe. Doesn't encourage international treaties and funding for supercolliders, y'know?

If the evidence is there, fine, and yes, we should look for it if the best theories say it's likely to be there. But the reference to particle physics set off the same alarm bells for me that the history of theoretical particle physics has: I'm not interested in finding new (and expensive and time consuming) ways to search for evidence of something simply because the old ways didn't find any. Sometimes when you dig for gold and don't find any it doesn't mean you should dig deeper, it means you should dig elsewhere, and the fact proving an unconventional theory is a great way to get your name in the history books is just one more reason to be skeptical of those making the attempt. Everyone wants to win a Nobel Prize like UTs Stephen Weinberg but no one wants to win an Ig Nobel Prize like John Bockris down the road at Texas A&M.