I think for the people against the ideas of parsers (at least for now), their point and argument is similar to those that are for it. In that the person who does that 1/10 output will still do 1/10 output and be fine for it in the content mentioned, even if an official parser were released. They'll still be worthless/terrible for their contribution, one way or another. A parser does little to change those people, other than serve as a tool to single out said person. While some may not see that as a bad thing, part of the reason it isn't made officially avail is the same reason as to why we can't single out people on forums.
If all 15 DPS in a WoD run are terrible, then a parser won't save your run. Asking them to step it up or leave won't work, as it's probably a DF run in 99% of any case. It's not a reportable offense neither, since that'd be implying it's against ToS to be bad at the game. Its official existence serves little purpose to those who don't care for it, and the fact it doesn't officially exist serves as that layer of protection against the sort of outcome that WoW had at one point. The parsers did not become mainstream use outside of the small number of people in endgame raids until sometime around TBC, especially WotLK actually, which is when raiding saw a significant growth in participation, and it was around that time that things became far more toxic as far as ridiculous expectations for simple content goes. Never underestimate how far your idiotic peers will go to misuse helpful tools. It's just like win-trading in TT and PvP. Devs underestimated the player bases tenacity to misuse or exploit tools given to them to do something. Just because only a few would do this, doesn't mean it won't affect the many (like with TT). The numbers game has a very powerful grasp on players in MMORPGs (and many other things really).
That was in reference to those games in particular.
Console users also don't have access to hacks that I'm aware of. Those aren't officially supported. Something being officially supported has far more importance than you might think. Obviously, hacks are more destructive, but they're still something that console users don't have access to, if we're going to use that as some defense about why something should be supported just because one has the potential over the other.
Look, I'm not against parsers at all. I'm 100% indifferent of them because I know the good that it serves. I also know the bad that happens, as I've experienced it first-hand over the years. I observe how things evolve (or devolve in some cases). I am against poorly constructed arguments though. And you need a GOOD and impenetrable one if you're looking to gain sway over a matter that the creators themselves don't support. That's not to say they won't ever change their mind, but these defenses aren't exactly any better than the stereotypical type that gets thrown around by both sides.