Weight is actually a good thing in the snow. Too light of a vehicle and it's hard to get any traction without something like tracks.
The struggling in the snow is most likely an issue of tires. If someone put some all terrain or ideally snow tires, I'm sure it'd do significantly better.
I don't disagree with that at all, it's a dumb vehicle no matter how you slice it and this debacle only furthers the proof. If it needs low rolling resistance, highway tires, then it's just a street queen for elon fanboys.