Permissions
Using racks
racks.use default: everyone Place racks, put items on them, change their pose and break them.
This is on for everyone by default because the original data pack gated nothing. A fresh install behaves exactly like the data pack did.
To stop a group from using racks at all, negate the node for that group in your permissions plugin. A player without it can still craft the item, but placing it puts the rack straight back in their inventory and clicking an existing rack does nothing.
Protecting builds
racks.use is all or nothing. To stop players breaking each other's racks in specific areas, use WorldGuard or GriefPrevention. Racks checks both before a rack is broken or an item swapped, see Protection Plugins.
Commands
Each command has its own node. There is no shared parent node, so granting one does not grant the other. Both default to operators.
racks.command.give - /racks give: hand out a rack of any wood.
racks.command.reload - /racks reload: re-read the config and language files.
A player who holds neither does not see /racks in their command list at all.