Wrong question.

Risk. Reward. Administrative cost.

The first of these I blocked when I looked at the domain and realised that the TLD were registering any old line noise. I'm not going to bother sorting that. Search for other experience turned up Blue Coat.

I subscribe to blocklists, and they update periodically. There are other levels of protection.

When a TLD is 99.9% malware or scams, it's far easier to block it outright. Registrars should take responsibility for what they're registering. Not my problem.