The rule says if the order of two actions/events is clear then the past perfect is not necessary, i.e. you can use past simple. So if the sentence has before or after then the order is clear and therefore the rule applies. The site here says the first sentence is incorrect. Is he/she right? If so, how do you explain what appears, to me, to be contradictory?
If the Past Perfect is not referring to an action at a specific time, Past Perfect is not optional. Compare the examples below. Here Past Perfect is referring to a lack of experience rather than an action at a specific time. For this reason, Simple Past cannot be used.
She never saw a bear before she moved to Alaska. Not Correct
She had never seen a bear before she moved to Alaska. Correct
They say "a lack of experience rather than an action". Saying that just does not solve the problem I have which is the past simple fits the rule of order of events. Not seeing is a negative event with the verb "to see".
I hope the answer won't be this is how we speak or this is how English works or since when languages are logical!