There's a lot of conclusion-jumping here.
The Gedo Mazo is and isn't a Tailed Beast. It's the body of the combined form of Kaguya and the Shinju without the Tailed Beast's collective chakra within it. When they're in it, it's the Ten-Tails.
But even though it is a husk of it's former self, it still has chakra of it's own. Even more-so, it's been treated just like a Tailed Beast in the series. When it remained within Obito after the Tailed Beasts were ripped out of him, he is kept alive by it and it's chakra and life force. And when it's not sealed within someone, it's summon-able and control-able.
Currently on SL, we don't treat it like a Tailed Beast. But it's properties shown in the series shows it to act just like one, even down to having a great amount of chakra, strength and gargantuan size. Heck, it's probably the most dangerous one to go against, since it can spit-out insta-kill chakra-absorbing dragons.
It is very clearly alive and a powerful being. Whether it should be treated as an item, claimable summon, all-around common summon for Rinnegan wielders or added to the Tailed Beast list is up to the community.