That site says digg is "hard". When digg had a comment structure similar to reddit, I used to comment quite actively, but too many political types were following me and creating a weird echo chamber, so I asked them to delete my account. 15 minutes later, my account and all my comments were gone. Maybe something changed when they removed that structure, I suppose.
When you say you “asked”, do you mean you had to write a message to someone requesting deletion? Because that counts as hard. Ideally the site should respect your use of a simple button.