1. They certainly weren't going to vote massively for Carter, but certainly a fair share of them would have.
2. If you notice, Anderson's voting patterns are quite similar to those of the democrats today, so the fact he was so strong in VT is also a kind of hint of it becoming a democratic State.
I'm assuming Anderson's votes would have split evenly between Reagan and Carter, in which case Reagan would still have won by a 6 point margin, which is pretty good (considering the South was closer)
In fact, Carter needed over 2/3rds of the Anderson vote to win Vermont, and I think that's pretty generous to Carter, even for such modern Democratic states like Vermont.
