Hello @Lacaterelle, welcome!
And noted. Good point. It seems that this function was not initially there in Discourse; only later it was added for accounts with one posts or less. There may be some other way that I have not found.
That said, admins can certainly delete accounts, and will do so if that's what people want to do. As I recall it, this only happened once, and @matthias dealt with it. If this is what you want to do, let him or myself know, and we will dig out the procedure to do it. Worst case scenario, it might take a day or two. Matt, I am sure you have archived somewhere the deletion procedure; can you put it on the manual? Or should I just add a one-liner saying "in this case, contact us"?