No undelete button if it was deleted from the blocked list

I was going crazy because I was trying to undelete a voicemail and all over the web everyone is saying that there’s an undelete button where I only see another delete button. But then I realized if you delete a regular voicemail there is an undelete button. The problem is when the voicemail is from a previously blocked number. If you go to blocked messages there is no undelete button, even if you unblock the number. Furthermore, if you delete a blocked message it goes to deleted messages and still no undelete button (again, even if you already unblocked the number). This happened because I get many spam/telemarketer/bill collector calls and I am used to blocking any numbers I don’t recognize. One day I accidentally blocked a Washington DC number and later found out it was a number for a political activist group leaving me a message about joining a conference call. While I’m not particularly interested in these calls, I also have no explicit reason to block them (they have my information because I gave it to them) so when I heard the voicemail I unblocked the number and attempted to undelete the voicemail. No big deal this time, but it begs the question why there is no undelete button for blocked or formerly blocked voicemails. It just seems weird.