Possibly unnecessary function call in geeksforgeeks union-find implementation

In this implementation of union find, I think in the Union function

int xroot = find(subsets, x);
int yroot = find(subsets, y);

function calls are unnecessary because we already find the parents of the edges in the iscycle function

int x = find(subsets, graph->edge[e].src);
int y = find(subsets, graph->edge[e].dest);

And pass the found parents to the union function

Union(subsets, x, y);

So again finding parents inside the union function is unnecessary. Can anyone confirm if this is valid and if not why