Why does this exchange bother me?

[ISP NAME DELETED]:
I have been seeing a VERY large number of visits from two hosts in
your IP block since August 26, 2005.
A list of all of the hits since Aug 26 is attached.
If you do not stop this/these hosts, I will be forced to drop all traffic from the [/24 IP block deleted] IP block.
Thank you for your attention to this matter.

Their response:

Best thing to do is drop the traffic.
Truly Yours,
[ISP NAME DELETED] Abuse Team

Ummmm, WTF? Did I miss something?