I think you are being a bit obtuse there..... if you want to argue the semantics then take it up with octapus I am just using the same definition as them.
Every unit of energy l use octapus purchase the same amount of renewable energy.
https://octopus.energy/blog/what-makes-us-green/
Anyways either way what ever.... My main point is that imo it's really good value. Any green credentials is just the icing on the cake.
The link you posted proves my point, they support and invest in green initiatives, the energy you consume comes from your nearest power station.