Apply Occam's razor
I could explain that "compassion" and "giving" end where a gun begins, and that those with the most to loot might object the most to being looted, but from long experience here I've discovered that trying to explain this to some liberals is often like explaining quantum physics to a goldfish.
A) This paradigm is so powerful it makes liberals' heads explode just trying to get their brain round it
or
B) The reason you can't explain it well enough to liberals is because it's a crappy paradigm.
Hmmm, which is the simplest explanation?
;-)