The STEP file claims the tolerance is 0.000001. Since the edge curve entities are shared by adjacent faces, the edges are identical. When everything goes as planned, there is no need to use a tolerance for the joining. The resulting edge tolerances, that are as large as 2.2531090370642774e-05 in your model, come from how far off the surfaces the edge curves are.
What do you think Rhino should do in this case, beyond reading in the data in the STEP file? One possibility would be to set the file tolerance to 2.2531090370642774e-05. This would not make sense when you import the file into an existing 3dm document but it might otherwise.