Chuck wasn't being rude, he was just suggesting you think about things a bit.
You have a list of people you have blocked. By blocking them you have removed them from your list of contacts and added them to a list of people who are not allowed to contact you. If you take them off your block list they will be able to contact you again should they wish to do so.
But if you really want them removed, click on each entry in your block list, then click on the button which says "Allow". This will transfer them to the list of people allowed to contact you. Close the window and go back to Messenger. Right click on each of those contacts you want to remove and select Delete from the pop-up menu.
Just don't be too surprised if some of them get in touch again.