anti-spam vs network abuse

As a result the ISP must either A) purchase more RAM, faster CPUs,
and additional servers, or B) run the risk of complaints and lost
customer goodwill. All of this costs time and money.

Looks like both a netscan and a portscan, and clearly not designed
to limit damages to innocent third parties. Come on,
this isn't rocket science. Turn down that scan rate by a factor
of at least 50, please.