Correct. Columbus's behavior was de rigueur for X=[those European engaged in exploration, settlement, and the slave trade]. It was also better than the equivalent behavior when X=[non-Europeans engaged in the same]. And the slave trade, conquest, and settlement was de rigueur for X=[civilizations].

Therefore "Columbus was bad" can't be meaningfully correct, unless we're presupposing a moral frame that stands outside of one's time and one's contemporaries -- and if we're doing that, I'll have a lot of other comments.