
We follow the lore because without it we're RPing in an undefined free-for-all of a fantasy kitchen sink universe where one person's canon is that only Padjal can become WHM's, someone else's canon is their character is the one special snowflake who became the only non-Padjal WHM, and another person's canon is that there's nothing special about being a WHM and anyone and everyone can become one. Put the three in a room together and you get immense IC confusion, narrative dissonance, and ultimately an OOC argument of Person A saying "we all need to follow the lore," Person B saying "only special people like me can break the lore," and Person C saying "screw the lore we should all do what I want."Â
I think it's pretty obvious why the causes problems and how following lore makes RP a smoother, less confusing, and less dramatic experience.
 However, I'm all for bending the lore where fit, and while I don't personally advocate breaking it I couldn't care less if someone does (if it bothers me that much, I won't RP with him/her, and that's the extent of it). I'm not trying to dissuade anyone from playing a WHM. I just think anyone who does needs to realize that A) They're breaking lore, B) They need to be prepared to face IC confusion/criticism from other characters for essentially breaking the laws of the universe, and C) They need to be aware of the possibility of the "lore nazis" screeching at them for violating the lore.
I also wouldn't personally advise taking the game's storyline as canon. According to the game's storyline, if you roll a WHM, you're the first non Padjal WHM and sure, it's not illogical that it could be the start of a trend and you're the first of many (unlikely, in that WHM are a rare thing to begin with, but hey, whatever). And according to the storyline, you also kill Gaius von Baelsur. I wouldn't take that as canon. You'll run into characters who are aiming to kill Gaius, characters who say that they already have killed him, characters who say he's still alive, and characters who say he's already dead. Personally, I'd rather distance myself/my character from the story's plot points as to not step on anyone else's toes nor have mine stepped on.
I think it's pretty obvious why the causes problems and how following lore makes RP a smoother, less confusing, and less dramatic experience.

I also wouldn't personally advise taking the game's storyline as canon. According to the game's storyline, if you roll a WHM, you're the first non Padjal WHM and sure, it's not illogical that it could be the start of a trend and you're the first of many (unlikely, in that WHM are a rare thing to begin with, but hey, whatever). And according to the storyline, you also kill Gaius von Baelsur. I wouldn't take that as canon. You'll run into characters who are aiming to kill Gaius, characters who say that they already have killed him, characters who say he's still alive, and characters who say he's already dead. Personally, I'd rather distance myself/my character from the story's plot points as to not step on anyone else's toes nor have mine stepped on.