First, yes, they are by any reasonable definition “concentration camps.” A concentration camp is any prison camp, usually a makeshift of flimsy one, in which people are detained en masse, often in substandard conditions, for an indefinite period time, and without any sort of formal process of criminal conviction. A concentration camp is not necessarily an extermination camp. Germany built its first concentration camp, Dachau, shortly after Hitler took power. It wasn’t until approximately eight years later that the wholesale slaughter began.
Second, the whole brouhaha over AOC’s (factual) claim shows what a shrewd politician and effective propagandist AOC is. In making her claim, she has successfully managed to shift the public dialogue to talking about the camps. Every time a Trumpist snowflake takes umbrage over AOC’s politically incorrect language violating his safe space, its point is being served: the camps are being talked about.