I fear you're comparing apples and oranges mate. Voice chat is a completely different beast entirely, it has it's own reasons why people are for it or against it besides RP reasons. It's a flawed argument to use that to try to prove your point here.
Same with your example of robbing people in real life... I don't even mildly see how that's relevant to our discussion here about OORP messages. Those two things aren't even apples and oranges, they're bullets and potato chips, they share no relation to each other at all...
I'm just saying, don't let something as simple and minor as // messages ruin the game for you. You're the only one in this thread who is making such a big deal over some OORP messages in-game, which leads me to believe that not many people view this to be as big of a problem as you're making it out to be.