It just hit me that I actually haven't answered the question at hand: would an optional official parser be toxic?
I guess I should analyze the implications of what it would mean first if it was official.
So say tommorow, SE decides to give the okay for an official parser. That means it would a parser created by their own hands (or whatever developer they want to use), slap it on ff14 for pc and ps4. Then they would probably iron out some code of conduct related to that, which I guess it wouldn't be all that different from the code of conduct they have in their ToS (no harassment of any form, etc etc).
Now we get to the nitty gritty of the playerbase and its usage of its parser. So, since this is an optional parser and it's private, it would essentially be the simplified battle log that we have in the game but with the "your own" settings and augmented to check your numbers cleanly and whatnot. So far, no reason yet for the parser to be any more or less toxic than the current situation the playerbase is in now because there's no way for anyone to actually see other people's parses. I suppose in cases where statics are involved and they're looking to recruit, they may request a SS of your parse through Discord but that still not anymore toxic than the current situation we're in. (Btw, I should clarify here that when I say this, I'm not saying the asking of ss is toxic. I just simply mean in the case of where someone doesn't take well being demanded a SS or the one asking not being civil about it).
I suppose the real question then becomes this then: In this scenario, when SE creates their own parser, to they ban the use of third party parsers that already exist, like ACT? or are they flexible enough to allow the use of both?
It's a very important question because if SE does decide to ban the use of third party parsers (again, in that scenario), then we're looking at a different kind of toxicity: resentment. I have absolutely no doubt in my mind that outright banning the use of third party parsers in support of one that only allows a private use would have some people irked at the very least. You have to remember that parsers can be used to help other people to foster improvement, not just because they don't have one but because having another person review the parse with you and giving you additional tips and information can prove at times to be even more valuable than if you were trying it out yourself. Banning third party parsers removes that, and in turn can build resentment. It would most likely be pointed at SE, especially at first but I'm not optimistic enough to say that it wouldn't leak in game.
On the other hand...
In the scenario where SE allows the use of both, then we're actually right back where we started, more or less. People ingame who challenge savage/ex content generally expect others who do the same to improve themselves whenever they can, as that community typically encourages one another to always try to reach the peak, so to speak. There wouldn't be any more toxicity that already exist in the game in terms of...quality (yeah, the quality of toxicity. I just said that. ugh /facepalm). But quantity? Well now we're looking at all the savage/ex ps4 players who will be expected to use this parser to improve themselves. "No real excuse not to use it" will be the flyby tag of this official parser. So the people who were already toxic to begin with simply have a wider scope of people they can target to be abrasive with. In contrast, the quantity of ps4 only players who always wanted to improve via parser means that now they can and by that same train, pc players who were mostly hush hush and had cloak-and-dagger meetings on how to improve themselves can now do it openly without fear of backlash or being reported falsely.
So I guess to sum all of this up, in my opinion, is that an official wouldn't see any more toxicity then we already have if third party parsers are also allowed, nor is it toxic in itself. However, banning the use of third parties parsers would now have a good chunk of people requesting that very same official parser to allow review of other people's parses and until SE complied with that demand, I more inclined that we'd see continual resentment against SE and possibly against some players as well.