Earlier quoted context omitted.
No, and this distinction is critical to understanding the risk that short sellers take. To use a slightly anomalous stock which hasn't split as an easy example, if you had shorted $BRK in 1980 when the price was $300, the potential upside was just 100%: In your best outcome, they go bankrupt and the most you earn is $300. Unfortunately for you, Berkshire Hathaway shares are now worth $430,000, so your $300 or 100% up…
OK, but the person you were responding to was asking if this also meant that the upside was unlimited - so in your example the answer is 'yes', if you bought in at $300 the stock price can just keep going up without bound. Can you clarify why these are different?
However, if you lose $300 that you brought to the table, that's your problem, too bad for you. If you lose $430,000 when you only brought $300 to the table, that's beyond being just your problem, that's the system's problem.
A system which allows this situation to happen is fundamentally flawed, it's vulnerable to exploitation and collapse if this kind of behavior allowed to go on unchecked.