Sakura was not written just to be disliked. She started off smooth sailing till they ran out of ideas for her. Other elements also contributed to her dislike among fans: she was a main character who was normal, so expectations were high for her (and unfortunately didn't meet them). Kishimoto wasn't focused and descriptive enough with her, which was frustrating. She had a tsundere archetype geared towards the person who had a crush on her, which a majority of fans were not fond of. Her physical appearance and attitude was often scrutinized on and was shallowly viewed as being mean and not pretty enough compared to other girls.
Kishimoto never intended for Sakura to be disliked, but he gave them enough reasons for that anyways whether he knew it or not. :(
That actually is a good point. But I would also like to add to that. Not only was Sakura rarely used in fight scenes, but also she has a very mundane and one note power set that does not make for interesting fights nor can measure up to other more over the top supernatural abilities that pop up in the series. How does super strength and healing measure up to to powers like Rasenshuriken, Amaterasu, etc.? If she was more Like Guy and Lee and had uniqueness to her Taijutsu and became a physical threat to the likes of Madara and Obito then maybe the complaints would die down.
Like an example of a fascinating tsundere that has fight scenes and a great and interesting power set for the setting she is in is Noelle from Black Clover. She has Water magic which seems mundane but her magic power is vast and she has spells for both offensive and defensive situations. so she has the ability And grit to stand beside Asta as both a love interest and as an equal.
But I digress, that does not explain the double standards of why Sakura is so hated though. Hinata is EVEN LESS USED in fight scenes than Sakura is and loses all personal fights she is in except against fodder and does not show to be a strong willed or determined girl like feminists like. Yet why is she so well loved?
I thought that she would expand on her medical ninjutsu. While Naruto and Sasuke were more adept in blowing up half a continent, she could have instead focused on healing. To develop a new way to healing faster, more efficiently during battle? Maybe even going on her own independent adventure for a time, helping those in need. And meeting new people and a mentor on the way. And discovering new cures? Or with enough ambition and courage, to figure out and learn Chiyo's forbidden jutsu?
And I always envisioned her to be an awesome gambler too, surpassing Tsunade in that field too . So many possibilities with Sakura, it's fun to think about it actually...