IMO, it's a big leap from saying that Koichi Tohei has some good skills to saying that I therefore understand what Mike or Dan is saying about IS/IP. The "we already do that" reaction is very common and, IME, almost always mistaken.
I appreciate that that's the case, I don't believe I'm one of those people. The reason I don't believe I'm one of those people is because I've met a number of people who've trained with either Dan or Mike or both, and nothing they've shown me is incompatible or stunningly different from the way I do things. Though as with all things of this nature, I am of course still learning. I'm sure it'd be interesting to go to one of their workshops if I get the opportunity.