The Roku employees reply was no help. We don't want answers as to why, we want a solution. I should be able to have all my devices on 1 account, but limit the apps on my child's Roku. FIX it! Make it an option to either sync apps or not. We already know we currently can't so your reply was a waste of time.
We appreciate your contact and feature request.
Currently, if you link multiple Roku devices to a single Roku account, the channels and purchases will be the same on each device. When a channel is added or removed on one device, the channel is automatically added or removed on all devices linked to that account that support the channel.
I've provided some links below to go into further detail:
How do I remove channels from my Roku® streaming device? | Official Roku Support
Do I need a separate Roku account for each of my Roku® streaming devices? | Official Roku Support
Please keep us posted if you need further assistance or clarification.