I thought it was kind of rude, but it depends on context. Did H.G. Wells and Joyce have a friendship, or did Wells just decide to write him a letter out of the blue? It is kind of rude to tell another person out of the blue that his book isn't worth your time, especially when said book took like 17 years to write.
Either way, I'm glad this letter exists, as it validates my priors :)
Either way, I'm glad this letter exists, as it validates my priors :)