There is no split-second decision about any card. The foul is committed, the referee stops the game, considers what to do, and issues a card if appropriate. The referee can take as long as he likes to decide on the decision of whether of not to issue a card. This was a rash very poorly judged (or even biased) decision that ruined the game for all the paying customers watching the game. Given the pitch positions of both fouls and the nature of the fouls, it is ridiculous not to believe that the Bournemoth foul was not more worthy of a second yellow and hence a red than the Richards 'foul'.
I have, not once, read a comment from you that a referee might, just might have got something wrong which leads me to believe that you will support all referees no matter how they perform or whatever the circumstances.