Why do I get jealous over a girl even though I don't want to be with her at all?

 Whether or not chapter 139 of Attack on Titan proves Eren was right is a matter of opinion. Some people believe that Eren's actions were justified, while others believe that they were wrong.

Those who believe that Eren was right argue that he was doing what he thought was necessary to protect his people. They point out that the Eldians were facing extinction at the hands of the rest of the world, and that Eren's plan was the only way to ensure their survival.

Those who believe that Eren was wrong argue that his actions were cruel and unnecessary. They point out that Eren killed millions of innocent people, including children. They also argue that his plan was ultimately unsuccessful, as the Eldians are still facing discrimination and persecution.

Ultimately, whether or not you believe that Eren was right is up to you. There is no right or wrong answer, and the story is open to interpretation.

Here are some of the arguments for and against Eren's actions:

Arguments for Eren:

Eren was doing what he thought was necessary to protect his people.

The Eldians were facing extinction at the hands of the rest of the world.

Eren's plan was the only way to ensure the survival of the Eldians.

Eren was fighting for freedom and justice.

Arguments against Eren:

Eren killed millions of innocent people, including children.

Eren's plan was ultimately unsuccessful, as the Eldians are still facing discrimination and persecution.

Eren's actions were cruel and unnecessary.

Eren was becoming a monster.

It is important to note that these are just some of the arguments for and against Eren's actions. There are many other arguments that could be made, and the story is ultimately up to the individual reader to interpret.