Credit where credit is due: this is a very objectively-worded poll, in my opinion. That's actually harder to accomplish than most people think (we ALL have an agenda, whether we admit to it, or not) so, Well done!
What frustrates me most about the arguments against mods are either:
1) Based on assumptions that are wrong -i.e. Mods doing what mods can't do, such as cheat. Essentially UI mods can take information that is already available in the UI, and present it in a different manner. That's pretty much it. They don't give you some super-secret info that no one else has.
or
2) Essentially blame the tools for the transgressions of the people that use them. eg., banning DPS meters will keep elitist jerks from kicking me out of their group because I'm not puling my weight, in their opinion. The problem with this argument of course, is that one, the DPS meter isn't at fault for the elitist jerk's behavior, and two, taking away the tool he is using to be a jerk isn't going to stop him from being a jerk. He'll just use something else- probably his estimate of how good or poor your DPS is, which is likely to be a lot less kind than cold, hard numbers.