Worried about what? He has no idea what could happen if parsers become legit, we have no idea either. Nobody has an idea: all we have is conjecture, just theories about how other games "supposedly" became toxic because of the recounts and damage meters. People are just afraid, nothing more nothing else.
I mean let's take in consideration Wow (worst game ever, yadda yadda, nobody cares): why did it become so toxic? Well, recounts existed a long time ago before the big ordeal happened and, in my opinion, what ruined the community were two things:
1)Gearscore: gear had no distinct "level" and so people were less inclined to find the best gear. Also, there weren't just one or two sets to get and I remember as a tank that the Moroes trinket was one of the best trinket, easily lasting until Black Temple.
2)Dungeon tool: because of this people had no more need to group up within the server, severing contacts and limiting the grouping only for raiding and perhaps some heroics (and even then heroics done in Dungeon Finder aren't daily locked).
Now I ask: which of these do we currently posses? Exactly, both. And these two features alone ruined a lot of the moments that made WoW fun and skill based: I remember that people were only caring for high gearscore and groups of people I knew were essentially ignoring everyone for doing dungeon tool, since it was more convenient.
It's not very different in FFXIV since that Item level gates all content, having higher item level "automatically" means you're better (even if your dps is higher than that "higher level player"), and grouping up in your own server is anything but convenient, since you even lose your roulette reward if you make a full premade. Why wouldn't I want the more convenient way?
This once again begs the question: "Why are we worried for a tool that, overall, has shown to be less harmful than say, "item level" and "Dungeon finder"??