The probability that you guessed right when you picked the initial door cannot change. Revealing additional information doesn’t retroactively change the odds that your guess was correct.

You had a 1 in 3 chance when you guessed, so the odds that your guess was wrong was 2 in 3. Those odds don’t change just because you gained more information later on. That’s why those 2/3rds chances that you’re wrong apply to the remaining door being correct.