That's an oversimplification. Macbooks tell you how many cycles the computer has left and give you a safety warning to have the battery serviced or replaced onc

That's an oversimplification. Macbooks tell you how many cycles the computer has left and give you a safety warning to have the battery serviced or replaced once you reach the 85% mark of usable cycles. You clearly ignored the service warning and/or the safety warning and continued to charge it. It wasn't a defective battery, it was the user ignoring (perhaps unintentionally) that their battery was no longer usable. Why should they replace it without charging for it?