Ya know, I don’t think anyone is a bad writer. It’s all about the taste of the reader.
Just like if you go to a museum and you look at a painting with extreme realistic detail. Maybe you think it’s awesome, another person would think it’s boring. But that same person may think a black square painted on a white canvas is amazing and you think it’s nothing spectacular.
So, in my mind, there’s no such thing as bad fanfics, books, poems, etc.