I actually agree with Stony, not sure why he has had a hard time. Firstly coins shouldn't ever be thrown and there is no justifying it. When Ferdinand got done it was after United scoring a last minute winner in a tight title chase (at the time) at our ground, in a derby that we was 2 down in and clawed it back after their players goaded our fans. Emotions were running very high and whilst I repeat coins should never be thrown the reaction came from all of the above which once more isn't right.
If you then compare it to yesterday, it wasn't a huge game. Chelsea was ultimately going to win anyway with the teams on display. It wasn't getting heated or nasty in any way and the kid scoring was harmless and not a Balotelli type of character that is hated. What is trying to be said is where the anger and emotion has built up in this incident to then start throwing coins is hard to work out.