It's only to be expected that any and all discussions turns into a furious (as in hotly discussed) debate. I support parsers, and I while I won't reiterate any counters that were made in regards to why the disdain of DPS meters exist (discrimination already happens, just that we can't say why, and quite a few of us already and continue to point out advantages to having parsers), I want to bring up two examples where a parser could help.
I normally don't give two shits about other's DPS in most DF and LFG runs, because as long as things die, that's all that matters to me. Now if you throw in a healer that couldn't heal themselves out of a paper bag while I tank (only starts healing me from 20%), oh boy it becomes a long and painful run. If I as a tank came #2, and not far from #1, I would be quite concerned, considering that the longer the fight went, the more chances I had to die, because the healer was slacking big time. In any similar case, I would call out the healer, but good DPS makes such a big difference in these runs. If one of the underperforming DPS was something I was familiar with (like any melee), with solid numbers and looking at what they were doing, it's an easy diagnosis there. I could then offer some advice if needed, but since parsers are in that limbo of "don't ask, don't tell," I can't say anything with perceived credibility.
Now in Alexander, the DPS are two monks, a machinist, and a black mage. On this run the machinist was top three with the monks, pulling more than 1k, the black mage on the other hand was hovering around 650 for example. You want to bet how many people would recognize how well the machinist was doing though? Probably zero. You want to bet who would be first to be kicked had the DPS shown signs of real struggling? The machinist, because even though this machinist was great, the "durr machinists suck" mentality is there, and people have no proof over who did what, but because they get such a bad rep, they are the the first to be suspected and kicked.
DPS meters aren't an "I win" button, they aren't replacements for practice, they don't turn people into assholes (because they already were assholes). They are tools. They can help pin point and diagnose issues, they can offer tangible and real time data on your performance, and you can use that with practice to tighten up your rotation. I don't like the "don't ask, don't tell" limbo parsers are in, and I like it even less playing a guess who game on where any given group can improve, but my main thing with a meter is that it helps me practice on improving myself. If I didn't have numbers, testing out different openers and rotations would be rather less solid.