Problem isn't Saloon.tf, problem is people's greed. Site that is potentially good for growth and interest into competitive TF2 should not be shut down based on an isolated incident. Don't let fear defeat you, stay strong my brother Sheepy.
That is if someone even did DDoS scrab because of Saloon.
Follow advice given by others to protect from DDoS attacks as standard, especially if you expect to be casted.
Also ETF2L couldn't ban Saloon from putting bets up on their matches, even if they tried. Only person who can is Cherry, though efforts can be made to find and ban those attempting to abuse the system, ultimately responsibility lies with the user, not the creator. This isn't the Atomic Bomb that's been created, it's a hobby betting website on virtual items.
Btw were ETF2L ever going to fix their rules regarding potential for abuse on Saloon? Been months.