I'm not saying that ML is fully in the right for keeping the "Counts" letters but I get why he is. He knows that the count is actually the Princess and before FL rewrote his story, he died at the Princess' hands.
He also doesn't know who the FL really is, so in his eyes there is no way of explaining without sounding crazy. " yes I'm keeping all your letters from the Count because he's actually the Princess, and the Princess killed me but I am alive rn. She's dangerous, that's why I'm monitoring all your letters in case she tries to use an alias".
Again, not saying he's fully in the write, and as the FL I would be royally pis***, but I see the angle he is taking.
He also doesn't know who the FL really is, so in his eyes there is no way of explaining without sounding crazy. " yes I'm keeping all your letters from the Count because he's actually the Princess, and the Princess killed me but I am alive rn. She's dangerous, that's why I'm monitoring all your letters in case she tries to use an alias".
Again, not saying he's fully in the write, and as the FL I would be royally pis***, but I see the angle he is taking.