"Or, that our policy on not doing a secure delete by default isn't something you agree with?"
This one. You have chosen a default that fails deadly. It's like designing a car that explodes when you turn it off. Oh, there's a button over here you can push to disable the explosion feature. That doesn't really make it better.
You've created an option that can and will deeply screw many of your users. The mere existence of the option is not wrong by itself. But the fact that it can and will so easily screw so many people means that the option needs to have lots of flashing warning lights around it and it needs to be on by default.
I just checked out the "Destroy" tab for my droplet. There is absolutely no, none, zero indication that failing to check this box will allow the next person to occupy my spot to read all of my data. Here is the exact text:
"This is irreversible. We will destroy your droplet and all associated backups."
"Scrub Data - This will strictly write 0s to your prior partition to ensure that all data is completely erased. Estimated Destroy Time: 11 minutes 22 seconds"
I would expect "destroy your droplet" to mean that the data gets destroyed. I would expect the "scrub" option to be for paranoid people worried about the FBI seizing your equipment and using electron microscopes to extract residual data. At no point does anything in here give me any expectations that the default is "hand over all of the data currently on the VM to the next random stranger who walks in the door".
Do you really speak on behalf of DigitalOcean? If so, you need to get your head straight fast, because this is not even remotely acceptable. You cannot defend the current practice, because it is not defensible. If you don't understand why that is, you need to sit down and think about it until you do.
Right now, as a customer of yours, my thought is this: if you think this isn't important and doesn't need to be called out, what else have I missed? What other crazy data leaks do you allow by default with the defense that I could turn them off if I cared? I hope and assume the answer is "none", but now I'm rather worried.
I can kind of sort of understand how one might end up building a system like this, thinking that it was a good idea at the time. But I cannot understand at all how someone could possibly defend it once it's pointed out that it's terrible.