Controversially arguably "legit" dodging is punished just the same as "rage" dodging because it's too hard to distinguish between the two.
And punishment for "rage" dodging is to stop people from dodging like a Jax just because they don't like what they see.
Ex:
"OMG, they went Taric and didn't pick Ali support when I asked them too. Trolls. Dodge dodge dodge."
"I'm 3rd pick and 1st pick both called and took my position. He's a troll for not letting me play the one role I'm good at. Trolls everywhere. Dodge dodge dodge."
"Ashe is not a real ADC. He's trolling. Must dodge dodge dodge."
"Darius is gonna troll us by stealing all our kills. Troll! Dodge dodge dodge."
(And don't get me started on how people will react when they see Trundle getting picked)