Eek! I find it slightly alarming to discover how many people have chosen to capitalise the words in Paul's list. The fact is, so far as I know, to capitalise these words is considered wrong by the vast majority of people concerned with the written word. (/me hides under desk while waiting for the onslaught of comments disagreeing with that statement

).
One can't find a logical justification for every single spelling or grammar rule, and often, it's simply the majority rule which applies. For example, there's no logical reason that I can think of for spelling 'wrong' with a 'w', other than the fact that convention dictates that we spell it that way.

The same goes for capitalising endearments, etc.
The only word in Paul's list which I think you could legitimately capitalise would be 'son' - but only if you were referring the Son of God.
Yvonne