What is he saying here? Why can’t I be compassionate if I didn’t suffer?

Maybe it’s a heritage day reference, in which case it translates into:

Only those well experienced in the agony of sub-standard seasoning will willingly and spontaneously lend out their garlic braai salt to an unprepared neighbour.

;D Ok, I get it. If you lend out your garlic salt you will suffer when the vampires come and do a house call.