I am unable to get rid of the Latest Snapshot from the drop down menu at the starting screen that shows all of the installations you have, and I turn off shapshots in the installations page but it is still there. As far as I know this is on Windows. I don't know if this is on any other computer type.
The latest release and snapshot are always within the Launcher and it is impossible to delete them. It default latest Java, which has to be downloaded in order to sustain functionality of the other versions. Closing the ticket as "works as intended".