i would have advised the flight attendant to confront him for removing your personal belongings and interference with your well being on the flight....

afterall that is part of your legroom that is too narrow to be (and its not) a common corridor, so why are they allowed to move stuff and walk over?

you should have told that a*****e that you paid for that extra space and its your space.... and if they touch it, accuse him of attempted theft of your personal belongings