Because Hanji deserves more appreciation from the fandom, and I do think they and Eren aren't that dissimilar.
"You know, Eren, we're more similar than you might think," Hanji beamed.
"How could we be?" Eren demanded grumpily, his exhaustion having eliminated any politeness he'd had. "I want to kill the titans. You want to save them. Weirdo," he added under his breath.
Hanji ignored the insult, having heard it enough that they scarcely paid it any heed. "We both want to save humanity," they replied, losing none of their cheerfulness. "I just happen to think we can learn more from studying the titans than from needlessly killing them."
Eren glowered. "Those things have killed thousands of humans! They killed my mother!" he exclaimed. "How can you look at them kindly, like pets or something?"
Hanji settled back in their seat with a sad smile. "Oh, Eren," they said soothingly, "so many people think like that. But we give a wild animal the benefir of the doubt, even when it could kill someone, don't we? So why not do the same with a titan?"
Eren lurched forward. "But—be—" he sputtered. "Because they're more dangerous than animals!"
"I think it's because we don't understand them," Hanji argued. "Supposedly, in ancient times, humanity feared bats, thinking them monstrous creatures. Now we know they're no more dangerous than rats." They sighed. "We never outgrow some of our childlike fears, I think. Did you know that Captain Levi still has a stuffed lamb to feel safe when he sleeps?" They giggled at their non sequitur. "But anyway, I am trying to overcome humanity's fear of the titans by attending to them myself. But never doubt that I am doing this for humanity, Eren."
Then as if in an instant, they recovered from their short bout of seriousness and returned to their energetic self. They slapped the table heartily and rose from their seat. "Well, good night!" they cried.
"Good night, Hanji-san," Eren said respectfully, biting back his distaste for their sympathy for the titans.
Hanji smiled again, seeming amused. "Ah, I see I have not yet convinced you. Well, I'll just have to try again tomorrow," they said breezily.
Eren groaned to himself.