The GCN implementation is based on the concept of templating (or lifting) which is not exploited in Scallop. In fact, this is the key idea of Neuralogic for joining deep learning and relational-logic representations.

It is explained in the paper "Beyond Graph Neural Networks with Lifted Relational Neural Networks" (https://arxiv.org/abs/2007.06286) and you also have a series of blog posts at https://medium.com/@sir.gustav