Why people rage
Non Delayers reason for raging
MOST people who don't delay enjoy sparring other people who don't delay because they can just spar without having to adjust to another persons delay (rather than patiently aiming for the large area of space ahead of the person)
Delayers reason for raging
Delayers are always stuck with delay, they can't help it. To them the whole entire sparring game is about patience and trying to aim ahead of somebody, they have become 100% used to doing it because thats the way graal forces them to play.
Adjusting
Delayer vs Delayer, both need to adjust to the hitbox differences.
Delayer vs nondelayer, the delayer doesn't have to adjust because he is used to his own delay, while the nondelayer has to adjust to the delayers hitbox.
nondelayer vs nondelayer, more skilled sparrer wins.
Advantage
In reality its not a huge advantage but having to adjust to somebodies hitbox to win a spar is still an advantage for the person who doesn't have to adjust.

"Get used to sparring delayers" well obviously you shouldn't complain and should just get used to it because delayers can't help it(unless their VPNing)
should be fixed tbh
Delay is something the game needs to fix somehow, it barely exists on Client Graal despite what country people are from, yet on iclassic it totally changes the sparring game.
Also true^ starting off as a noob with delay is easier than starting off as a noob without delay in spar

conclusion
delay is annoying af but unitl something is done about it by graal, dont complain, just learn to adapt. even tho it sucks ass