Appearances can be deceptive.
I remember Chiba Sensei once saying (to paraphrase) true compassion is having the ability to destroy but not destroying [your opponent] which sums up both practical and philospohical elements for me
For what its worth, this is pretty compassionate, but far short of "truly" compassionate. Lat met throw two principles at you:
1) Since action begins as thought, aggressive thoughts (to harm or hurt another) are, in some sense, as bad as the actions themselves.
2) The boundaries between one person and another are illusory.
if we are all one and the same, then allowing someone to harm you is as bad as harming another person. I.e. turning the other cheek is right out, you might as well mug somebody yourself.
Furthermore, allowing someone to THINK of harming you is as bad as harming them yourself. Bad karma that you will have to pay back at some point.
So true compassion would involve being a person for whom it is impossible to be "an opponent" in the first place.
Like when a swordfight ends before anyone makes a cut, because one guy realizes the other guy just has no openings. The state I am talking about is one where the thought of drawing a sword never even occurs...he's not even a would-be attacker.
I think that's true compassion. If I ever get anywhere near that state I'll let you guys know all about it.