> If you're already using IPv4 there's no reason for the extra complications of leaving IPv6 enabled.
That’s just flat out wrong. No pure IPv6 deployments exist on endpoints in practice. Only in internal networks. You either run pure v4, or dual stacked v4+v6.
IPv6 is gaining some pretty solid adoption these days, but it’s not there yet. Disabling it is holding back the deployment of it, and is a problem by itself.