I wouldn't normally boo a player, but if a player has been extraordinarily ordinary for a long time, like it has been with Schneids, he needs to know people are watching him. The fact this is a big story for Evertonians, means it doesn't happen very often, so its not like Evertonians go and boo whomever they are displeased with at that particular moment.
If he was a man about what happened, he would take it into his stride and actually give a sh** from now on. It's not the end for Schneiderlin, as long as he turns a new leaf and starts playing to his potential.
Or perhaps we're all wrong, and that's just the way he plays, he's not a tackling DM, he just helps move the ball sideways.