I can understand people engaging in telemarketing (because they're evil), but I don't get the point of making a call that you know ahead of time with absolute certainty is not going to end in a sale.
Fucked up incentives. Presumably because calls statistically leads to sales, someone was ordered to increase call volume. Presumably cold calling random people could get them in more trouble with the FTC or is against corporate policy, so to deliver on that they're making pointless calls. That the sell-through rate drops in proportion is muddled by competition, random variance, pricing policy etc. so the executives probably don't know it's happening. That kind of corporate dysfunction is quite common when employees don't have any incentive to run the actual business well, just according to the metrics.