Yes, your are totally right. Actually, it's a meaningful limitation; but they forgot to do it in registration process too.
So, for now, you can temporary remove this limitation from remove account process until flynax add limitation in registration process ( maybe they did it in 4.7.1 )
Go to your_template/components/account_removing/_account_removing.js
Find:
Code:
Only registered members can view the code.
replace with:
Code:
Only registered members can view the code.
There is same problem in Remind password process and you can modify it too.
Go to includes/controllers/remind.inc.php
Find:
Code:
Only registered members can view the code.
Replace with:
Code:
Only registered members can view the code.