Seriously, people should stop blaming him for his decision.
Spoilers ahead!
Summary:
- Some fans feel that Armin betrayed Eren at the end of AoT, but that is a misconception.
- Armin not supporting The Rumbling is absolutely normal.
- Eren knew that his friends would have to stop him.
Attack on Titan (Shingeki no Kyojin) finale was controversial for many reasons. Many fans felt it was too rushed, while others felt explanations and plot points came out of left field and had nothing to do with the previous story.
Others felt that the characters didn’t behave like themselves in the finale of AoT. While this can be argued for some of them, a commonly brought up example is Armin. In the end, Armin decided to side with humanity and not support Eren. In that sense, he, supposedly, betrayed Eren.
That notion, however, hinges on the fact that Eren was right in starting The Rumbling — and if you think so, you miss the point completely.
It’s perfectly fine that Armin didn’t support the genocide
Eren starting The Rumbling means 80% of the world’s population will die. Essentially, Eren commits a genocide at the end of the series. He was forced to make a choice where two options were terrible, yes, but this was absolutely not the way to go.
If you are siding with the Yeagerists and think the rest of the world should be destroyed, you are wrong — the entire point of AoT is that tribalism and racism are wrong. Of course, Eren becomes a villain in the end, and Armin doesn’t support destroying the world.
Eren knew his friends would have to kill him
There’s no “betrayal” to speak of, because Armin never supported the decision to genocide the world in the first place. He’s his own person, with his own opinions and principles — he never betrayed those. He was never blindly following Eren.
Besides, Eren knew that what he was doing was wrong. He knew his friends would have to stop and kill him, and he acknowledged that fact. In that sense, Armin actually did what was expected of him — and so did Mikasa, who ended up killing Eren to save the world.
Attack on Titan finale has its issues, but this is not one of them
It is understandable why one might be upset with the finale of Attack on Titan. Many things definitely happened too fast, and some characters didn’t get their proper endings. There was too much symbolism that fans felt wasn’t needed, and some felt that the ending was a bit too hopeless, with the “war never ends” message.
However, if some characters had their own stories closed properly, it’s Armin and Mikasa — and to say that Eren was betrayed by his friends is just wrong.