I think that’s because it seems like the OP misunderstood what was being asked of them. I think you’re 100% right here (having gone through this exact process and choosing, exactly as stated, to remove Activation Lock/Find My via my personal machine rather than a store machine) but OP seems to think they were asking for his phone passcode. That doesn’t make sense to me but it looks like that’s what he’s stating - phone passcode, not iCloud login - and I think that’s causing the misunderstanding.