Well, not following the RFCs is bad, but I can see why they do it.
Most people using low TTLs probably don't know what they're doing, and if you're a big ISP having to constantly make recursive queries hurts page load times for your customers, who'll blame you.
Most people using low TTLs probably don't know what they're doing, and if you're a big ISP having to constantly make recursive queries hurts page load times for your customers, who'll blame you.