A very well-put response ranai.
There is room for all the approaches to dishing out pain, but I feel that those who have judged doms who simply enjoy inflicting pain as 'not reliable', 'selfish' and 'dangerous' are denying that room.
Personally, I am not a big 'pain slut', but I take it willingly from my Mistress for whatever reason She likes, even if it is just because She feels like seeing my ass reddened. I take great pleasure from satisfying Her desires.
I can completely understand relationships where pain (or any other torment) is only for use for certain reasons... but please don't be so judgemental of relationships where it is for use for OTHER reasons.