It depends on what is causing the lack of supply. If the bottleneck lies in factors beyond the control of consumers, i.e. discontinued production, or shortage of raw material, then I see no inherent issue with scalping. But if it’s the scalpers themselves that cause an otherwise plentiful supply to become scarce, then they are the cause of the shortage, rather than the effect, and their behavior should be curbed. The problem is that the former situation can easily lead to the latter via a panic buying feedback loop, and it’s not entirely clear where the distinction should be drawn.