Pretty sure you are wrong as I see countless people get banned for saying I don't care. Still, what you say is also true, but that rule is misunderstood a lot of times.
For others who are confused by this rule, here are some examples
OP: "I have a dislike for cheese"
"Who cares!" <-- This would be bannable right off the spot as he is dismissing the entire topic
OP: "I really dislike cheddar"
"I don't really care about cheddar, I prefer pepperjack myself." <-- This is not dismissive to the entire topic, he presents a dislike or disregard for a part of the discussion