The script kiddie bot netters are pretty likely to ddos, because it takes little to no hacking skills (just like bot netting.)
I find it highly unlikely that there is one guy somewhere who has a monster LTC mining rig as well as a monstrous botnet that is so huge he is simultaneously successfully DDoS'ing the 4 largest LTC pools by himself. I am fairly certain there is at least a handful of individuals in on this, i.e. a "private pool" - please note the quotations indicating that the phrase's intent is not to be taken literally but in a subtext.
Ah, OK, I get you. Yes, this is definitely the work of a group of people.