All cultures and religious aspects aside, throwing a shoe or exposing the sole as a severe insult is about akin to tossing a stapler or exposing the internal staples at your enemy.
If a select few believe it to be an insult, then it is for that person/people. However, everyone else will look at you, while blinking, and ask if you are finished so everything can carry on again once the fiasco is done.
Pretty fruitless, and definitely not something you do as a global statement aside from attempting to make a mark on the world through a form of ethnocentric action. It’s about like doing an American style (well, what we here in America do at least) peace sign in Australia. Performed in certain hand pattern, it is the same as the middle finger.
Besides, the insult is the exposed sole, not the entire shoe.