How the author, writing more than 3 chapters is lazy ?
Read it again. Slowly. I wrote, writing an arc specifically entailing amnesia is lazy writing. It doesn't mean the quantity of the chapters but the essence of the story. Amnesia trope is easy and cliché. They could've done different stories in the amount of chapters they've stretched with the amnesia trope. That's lazy writing.
Alot of authors use this trope. It's well known for being fillers/space holders. This story started out unique and fresh, which is why it's even more disappointing.
Maybe a cute three episode is fine (like hosiks story) but a whole arc feels like lazy writing imo