Isn't it obvious DT won't always agree? There are clear red and clear green cases, but in between there's going to be differences of opinion at some level.
okay you have just summarized the whole issue in a very nice short statement which i couldn't do due to the lack of writing skills

.
i do not think anybody will debate over the "clear" red and green cases. but what's up with the gray ?
if you tag someone for being a scammer, not a single DT member will counter it and say " no allow this guy to scam others". it's pretty obvious !
but what happens when a DT member goes out of his way and tag someone for saying "lemon"? what if no other DT member give a counter tag to the lemon tag?
who can accuse the lemon hater DT member of "abusing" the trust system when there is not a single rule that says "you can't tag someone for using the word lemon?
the tagged person will have his profile painted in red, he won't be able to make any deals with any sort of flexibility, he will be kicked out of any signature campaign even if he gets a counter rating "since most camp mangers clearly say that if you have a negative rating from a DT member you won't get paid".
who will protect say "me" from you giving me a random negative trust because i use this smiley

way too often ?
for all i know no are not breaking any rules for doing so !.