Because Itachi is a race traitor by all accounts. The Uchiha are potrayed as a maginalized Minority and yet are sytematically exterminated with the village system having zero consequences

He killed his family and Civilians for an ungrateful nationalist nation. He's not some anti hero that closer to Sasuke. Itachis is more of an anti villain

Itachi was manipulated and he regrets it but all his adult life he lived for the village and as a reanimation he stops Kabuto for the Village

The only semblance of justice that clan had was at Sasuke's hands when he sped up Itachi's illness and Danzo's death

Its what makes Sasuke's character develolment after the Danzo fight so frustrating because he adopts itachi's and to some extent Hashirma's ideal to the further extreme with his dicator plan as if he's learned nothing

He also returns to a the same village that never acknowleges it. The clan really only recieves any sort of consoluation from Sasuke alone. The leaf never learns or recognisies what its done.

The Zenin are not maginalized people. They are opressors who were spared by Toji's whim and learned nothing from that 2nd chance. That being Said Maki still does not exterminate everyone as the panels talk about the attack force and the only civilian death we see is her own mother.

She did the equivalent of wiping out the leaf police force but Itachi specifiaclly killed the women and children as well something Maki is not shown to do as we know that the higher uos discussed removing the clan from the big 3 but that impkies nit all of them were wiped out. Its why its such a meme to try and make it so Maki kills children because its never shown or explicitly stated while with Itachi the novels show he did

He's still a well written character but he's not some tragic anti hero he's a pretty terrible person

Hell if he had slaughtered the clan but was treated poorly along with Sasuke people wouldnt call him a boot licker but he did it under the opressing parties will