I find it strange.
It seems this kind of attacks are happening very frequently these days and most hosters seem to not apply enough safety measures.
What does need to be prevented if possible is the nature of the people who have enough time on their hands to run these sort of idiotic attacks, enjoying the chaos it creates... IMO, these are sick people with no lives of their own.
As a business we have spent a small fortune on this defense but no more we just turn off that server so it goes to our backup servers on a different address.