This shouldn't be a factor because your password should be a random series of characters that are unique to that site.

> I believe that I can - to some extend - remove myself without having to go through whatever crap account deletion process that services has tried to cobble together.

To an absolute minimal extent: you can make it so Google won't tell them whatever it was they already told them again. But you can't make them delete the data that they already lifted from your Google account.

For keeping surfaces out of your inbox, that's what email aliases are really good for. Register with an alias and then block that alias if they abuse it.