the shoe was actually not thrown at him, it was thrown towards him at an angle so it wouldn't hit him. His way of protesting was wrong, however it opened some eyes in the congress party, they denied votes to Sajjan kumar and jagdish tytler. We can relate this to Bhagat Singh ji's assembly bombings, the grenade had no shrapnel and was thrown in an open space, just like the reporter had no intentions of hitting the home minister.
"It takes a loud voice to make the deaf hear."-S. Bhagat Singh ji