It's not that it's "hard" as much as it's annoying. When every react component has its own fragment, writing so many graphql fragments gets annoying. Going to graphiql for each fragment is annoying. Figuring out what fragments need to be spread on a query can be annoying. It's just more stuff that you have to keep in your head.
With that said I still like using relay on my random react-native side projects.
Even better, all of this stuff is integrated into language servers with typechecking based on your gql schema, auto completion, and all the minting checks we’ve come to expect. Is a field nullable but you’re only handling to non-nullable case? The editor catches it.
I think this is a classic case of anecdotes not adding up to data.
writing queries is stupid easy if you use a tool like GraphIQL especially with the explorer.