> will installing snapd not install AppArmor as well?
It can't, because AppArmor is a kernel-level feature that also requires some level of integration into the rest of the distribution. Red Hat/Fedora-based distributions already use SELinux in place of AppArmor, so using snap on those systems can't have full security capabilities (making SELinux and snap work together would be non-trivial, and I don't think anyone is motivated to do it).
Flatpak uses other mechanisms for limiting the access that applications have, so does not rely on either AppArmor or SELinux being on the host system.
