It may also lead to interesting discussions within the fan community. Fans could debate about what Naruto's character really means, what the appropriate boundaries are for fanfiction, and how to balance creativity with staying true to the source material.
On the positive side, it could encourage more 'true - to - the - character' fan works. Fans might start focusing more on creating content that Naruto as a character would actually approve of, which could improve the overall quality of fanfiction in the Naruto community.
Some fans might be discouraged. If Naruto is depicted as hating fangirls' fanfiction, those who write or enjoy such fanfiction might feel like their work or interest is not respected. This could lead to a divide in the fan community.