[2021] Are ladders & 2nd floors a cheese strat?

There was a time when this was cheesy, because the AI pathing was lacking and zombies had nothing productive to do in this situation. But now they should attack the blocks holding up your second floor. Like others are saying, withstanding a horde doesn't necessarily mean your base is cheesy. Withstanding every horde with no effort is a different matter, in this player's opinion.