No, many of us who are against parsers in game or open parsing arent hard against parsing all the time and have probably added up our battle logs ourselves from time to time to see how we perform or which DPS we might want to use in certain content.
What we dont want is for a situation where gamer(tm) types are giving sprouts and people who are cutting their teeth at harder content shit over their parses in ARR/HW/SB/ShB content. Or rolling into casual fun runs and lambasting people. Which is exactly what would happen.
If you regularly runs blinds it can be a nighrmare not to have some idiot roll into the group gabbling on about the guide and wondering why people havent got a walkthrough open on another screen, or enter a blind prog and are surprised to learn that you actually have to set aside an hour or two to actually prog the damned thing.
Imagine giving those people an in-game parser? It would be a right pain in the arse.