Board Thread:Theories and Speculation/@comment-45444155-20200621203703/@comment-6769189-20200622032211

Its not it only takes damage from Senjutsu, it is just significantly more vulnerable to Senjutsu.

The series explained it(although Naruto himself barely understood) as natural energy could be used against natural energy

For whatever reason, the TTJ's natural energy gave them an extra layer of protection that regular chakra couldnt break through.