DDOS itself isn’t a single attack. It is a name that is applied to a large group of attacks, it’s like calling something “cloud”. As a result as attacks continue to change whatever is blocked without affecting your droplet or other services is immediately mitigated on our end. However, as the attacks evolve some of them may be able to get through the measures that we have instead in which case the droplet is “dropped” - which basically removes the IP, and removes the attack, the unfortunate side effect of this is that essentially the droplet is down. We are constantly improving our backend mitigation for DDOS attacks across our entire network but this is an ever evolving landscape.

Well the above answer is as vague as it can get.
Scripted responses !
I very well understand what DDOS is and since droplet goes off network, I cant even determine what sort of attack was that. It is usually a reflective dns ddos, however droplet is of no use when some attack happens. No protection and leaves you helpless.
I have migrated to other cloud providers and it works great for me !