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.
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.