How would an optional, official parser be toxic?

[Penthea]

Yet, I have no benchmark with which to determine if I am doing the best I can for the gear I have, or if I really am bad.'

This is where a lot of parser toxicity begins. Many people just glance at the parser and use the numbers presented as if they're the only defining factor of a person's performance. Often they don't look at ilvl or if the gear doesn't have ideal stat weights. Being the lowest dps doesn't mean you're the worst player. You could even be the best player if the numbers you're producing for the gear you have are amazing.

The main context for performance people often use is their own. They judge other people versus their own performance. This is flawed if you don't take gear into consideration. Someone might look bad compared to you but if they're 15 ilvls lower...then no wonder?

People reading this post will likely think "but of course I look at their gear, anyone would" and great if they do, but my time in WoW taught me that it is very common for people to not take gear into consideration.

Of course someone doing great dps in bad gear doesn't mean they do enough dps for the fight. In that case if you remove them you can just say to them "sorry your gear isn't good enough for this fight". But if someone only looked at their numbers and didn't bother checking the gear may instead say "learn to play your class properly" and this is where arguments can start. The player about to get kicked may be aware they have good numbers for their gear and of course they would usually try to defend this. Or even worse the person isn't aware that only gear is holding them back and they may end up feeling that max lvl content is out of their reach and might respond with comments relating to elitism against beginners.

The problem with parsers is that too many people use a mere glance to judge the potentially more complex situation of their fellow players. They can make people lazy, and therefore often inaccurate, when it comes to judging others and/or themselves.