Mirror Sync and Folders not Being Deleted on the Right Side - Don't understand what is happening

[Radish]

FreeFileSync v10.15 x64
Sync Type: Mirror
OS: Windows 7 Pro. x64

In the left location I have the following populated folders containing the running files for the said applications:

E:\PORTABLES\JAVA 1.8.0_201 [PortApps]
E:\PORTABLES\LibreOffice Still [PortApps]
E:\PORTABLES\Opera 60.0.3255 [PortApps]

I have for the last few months been syncing these folders to the right side (of the Mirror sync). The root location for that right side sync would be (using a drive label):

[HDD PORTABLES]\PORTABLES

I decided that I didn't want to sync those folders to the right side anymore, but I did want to keep them and their contents in case I did want to use them, I just wanted not to sync those folders. I rarely use the applications and thought to just pack each one into a single archive file using 7-zip. I made the archives so I now have the following files that I do want to Mirror sync to the right side:

E:\PORTABLES\2019-08-22 - JAVA 1.8.0_201 [PortApps].7z
E:\PORTABLES\2019-08-22 - LibreOffice Still 6.1.6.3 [PortApps].7z
E:\PORTABLES\2019-08-22 - Opera 60.0.3255.55 [PortApps].7z

To avoid the folders with the apps files being synced I set the following Exclude Filters:

*\JAVA *\
*\LibreOffice *\
*\Opera *\

I then had FFS do the Compare and found that it did, correctly, show that it would not sync the excluded folders. It also showed that it would sync the '7z' archives. Fine so far. (Though on thinking back FFS also didn't show that it would delete the three folders (and contents) on the right side.)

However, when I did the actual sync, I expected that FFS would delete the already existing folders on the right side, put there by previous Mirror syncs, namely:

[HDD PORTABLES]\PORTABLES\JAVA 1.8.0_201 [PortApps]
[HDD PORTABLES]\PORTABLES\LibreOffice Still [PortApps]
[HDD PORTABLES]\PORTABLES\Opera 60.0.3255 [PortApps]

This didn't happen. FFS sync did not delete the folders on the right side - I had to manual delete them myself.

On thinking about this it doesn't make any sense to me. Surely a Mirror sync should replicate the left side to the right side with the exception of items covered by Exclude filters (and I would assume also with the exception of any Include filters if they were being used). So why didn't this mirror sync automatically delete the folders on the right side? Was there something about the Exclude filters that prevented the deletions on the right side of the folders I no longer wanted there?

[xCSxXenon]

When you set those exclusions, that stops it from moving, copying, and deleting those exclusion. FFS didn't even attempt to detect any differences for those three directories, it just lets them be. It didn't detect that it should delete them on the destination because you explicitly told it not to even look at those directories. The exclusion list is not a "don't mirror this to the destination" list.

[Radish]

Okay, I get drift. Thanks very much for your response.