Because bots will do it at a much larger scale than individual humans. The first law of web robotics applies here: the bot should not harm the website it's craw

Because bots will do it at a much larger scale than individual humans. The first law of web robotics applies here: the bot should not harm the website it's crawling, or through inaction allow it to come to harm. I didn't read the article due to the paywall, but I assume that the problem is that the problem is that these goods are reserved for that (non)-customer until the shopping cart times out? That is directly costing the merchant money, either in lost sales or having to maintain extra inventory. So yeah, that bot really should have been programmed to end the session with an empty basket one way or another.