How can I disable snaps in gnome-software centre?

Pretty simple, just remove this package, stop & restart gnome-software. (easiest thing to do is just reboot..

sudo apt purge gnome-software-plugin-snap

Then reboot & you'll not see snaps in gnome or ubuntu software app

I also dislike snaps. I don't use them, and it's annoying how it's always phoning home for updates. Unfortunately in Lubuntu 16.04, lubuntu-desktop has a dependency on snapd, so it's awkward to just remove it.

You can at least permanently kill it by doing

sudo systemctl stop snapd
sudo systemctl disable snapd