This graffiti means
I who is constraction worker love constraction worker.
Man's world is the highest.
I am requesting same constraction worker!!
I think that the same person wrote a couple of this scribbling.
I feel the soul as for either scribbling.
It is mysterious because these seems to shout so that these is written by the character.
(A public lavatory in Japan is used as a meeting place of gay person.)