If states can appoint electors based on the popular vote, they can do anything. The rule of law is gone.
I don’t see why that undermines the rule of law, when the Constitution authorizes State legislators to provide any method they want for appointing electors. They could pass a law providing for electors to be chosen by a coin flip, by an arm wrestling contest, or by the Prime Minister of Sweden if they want. They are just accountable to the voters, who, hopefully, would vote them out if they did something that stupid. Just as Virginia’s voters should punish their own legislators.