Time Machine - File Vault weirdness

I have two accounts set up: my "regular" user account, and a separate account that I have set up with FileVault to test this feature. The FileVault account is set up in TimeMachine to not be backed up.

However, when I log into the FileVault-protected account, then log out, TimeMachine starts to back it up, which I then cancel.

I am wondering if I have the "omit" set up wrongly. I set it up by selecting the name of the user under Macintosh HD/Users.

 

I seems as though this is the case.

In other words, if you turn on FileVault, you are forced to also back up the account. IMHO, this is a design bug.

Unfortunately, for some reason it seems to take incredibly long to back up the account, wastes a ton of space, and worst of all, makes my machine inaccessible during the process.

I find this "incredibly user-unfriendly" and as a newbie to the Mac and quite surprised by this. It is an intolerable situation, that I have to find a remedy for.