I love Marinette, and I honestly think I might’ve done the same in her situation. But I also think Alya was right, and her reaction in Revelator is completely understandable.
Alya wasn’t just upset for no reason. From her perspective, someone who terrorized the entire city and was about to kill her family (like in Sentibubbler) was suddenly being treated as a hero.
I’ve also seen people criticize Alya by saying it’s hypocritical for her to hate lies when her Miraculous gives her the power of illusion. But I don’t think that’s a fair comparison. Using illusions as a superhero power isn’t the same as lying in personal situations, especially when it affects people’s trust.
On top of that, Alya has always had a strong sense of justice, which is a big part of why she disagreed with Marinette here. It’s not just about the situation itself, but about what she believes is right and wrong.
Alya was upset because Marinette decided it was her place to choose what Adrien should or shouldn’t know about his own family. That’s a huge decision, and it makes sense that she would react strongly to that.
Later on, the situation becomes more complicated. >!In Heartfixer, Marinette admits that part of the reason she keeps hiding the truth is because she’s afraid of losing Adrien. It doesn’t mean she lied for selfish reasons at the start, but it does show that personal fear becomes a factor in why she continues the lie.!<
Overall, I think both Marinette and Alya had valid reasons for how they acted, even if the situation was complicated.