There's no reasonable reason not to have a parser built into the game (technically, it already is built into the game, but players don't get to see that one). Parsers aren't difficult to obtain, and everyone who needs one or wants one already has one. But this game isn't like WoW where a parser had add-on support, and sharing the information with a group was as easy as linking it into chat; even then, it was preferred that everyone in the raid had a parser running.

Putting up with ACT and the inconveniences it comes with is a silly thing for players to have to do in an MMO that just had an xpac in 2015. The most you'll hear from opposition is a boogeyman argument of "the parse troll", which seems to suggest that handing a player a parser will suddenly transform them into an obnoxious elitist who kicks players with impunity because their number aren't within 1% of perfection. It's ludicrous.