There response to your suggestion would be something like "We've never experienced the act of Satanic sacrifice but we're not going to wait to experience it before we condemn it"
Fanatics of all types won't even consider the inherent logic in your statement.
The fact is, there are also wack jobs in the martial arts who approach what they do as a religion. People who are theist or non-theist need to be aware when they've met that type of instructor or organization.
The group/site we are discussing goes too far, and so do many martial artists with their secret spiritual-death-touch-life-force-jitsu techniques and their Grandmaster-Holiness-Shihan crap.
IMO there is nothing in traditional or "new" Christianity that can make a LEGITIMATE condemnation of any martial art.
Read the rest of that site. It's chock full of personal opinions that are loosely based on scripture. It makes me ill when people take a good piece of scripture and use it out of context. The idea that these people think that they're evangelizing, and thus bringing people closer to Christ is ludicrous. The reality is that any martial artist that is on the fence about Christianity is going to read that site and say, "this is what they believe?" And then they'll walk away. Oh well - so long as the author gets his point across....