It doesn't take a nerd or genius to use a botnet or ddos in general. There is public tools out there, and botnets that you can pay for, its that simple. It only started getting more popular in the KO scene the past couple of years when you get owners that don't give a fuck about their players and are in it strictly for the $. They're the ones who want to eliminate all their competition. DDoS/Botnet has been around for a long while.
Edit : When you open servers these days, if you're not prepared for DDoS, theres no point in opening. You're almost 100% guaranteed to get ddosed. I dealt with it for 3 weeks and was forced to change hosts.