My dad, watching me tear through zombies with a machete in Left 4 Dead 2.
"Don't you think this desensitizes you to violence?"
Me, sarcastically: "Yup, this is completely desensitizing me to grey pixels becoming red pixels"
"No, really. This is teaching you terrible lessons about how to relate to people. It's telling you to solve problems with violence."
Me: "The problem I'm solving requires self-defence."
"Killing indiscriminately is self-defense?"
Me: "I'm not killing indiscriminately! Look, I'm not killing Nick, or Rochelle, or Ellis, or that Witch..."
"But you are killing all of the zombies."
Me: "Killing a zombie is inherently an act of self-defense, as all zombies by definition are soulless killing machines."
"Couldn't a game teach you the same lesson about, for example, Muslims?"
At this point I was literally speechless, dumbstruck, and other words that also mean "unable to speak because that argument was so poor". How could a game like that get past the ESRB, let alone Faux News and CNN?
TL;DR: My dad said that video games might teach me the terrible lesson that killing a Muslim is inherently an act of self-defense, as all Muslims by definition are soulless killing machines.