The broader Simon Serrailer series was my favourite as a teen but this book is just not it.
Transphobia being excused as okay and the main character constantly misgendering a central character and never once being called up on it. Simon talking about how he didn't like assumptions being made of him due to his difference but allowing and perpetuating the same behaviour to others. 
Hill is an author who tackles a variety of social challenges through her books, usually with research and degree of nuance and variety of perspectives (albeit all with undertones of privilege through her almost exclusively middle class central narrators) shown. She simply did not afford that towards the trans community and no younger, more understanding or more liberal opinions were ever expressed to go some way toward offsetting the complete lack of consideration, care or (even attempted) understanding shown in the narrative