If the lift gate is up, you are allwed to pass. If it's down, 'you shall not pass'. It's still about legal access after all. The road is blocked and the access is prohibited.
Reading the wiki yeah? The one where edits are made by that single user we should not care about?
Don't expect people to have the ammount of time of an unemployed, the willingness to read all the discussions or the knowledge where they even could find them. Since knowledge is acquired through long years of mapping it obviously does not grow on trees ready for harvest and just waiting for you. The majority of OSM users for sure want to map and not participate in dry, longlasting discussion.
In this discussion I only could find how it shouldn't be done - not how it would be done.
The main question still is HOW you would tag the opening hours, the access or whatever you want to call it. For the end user and a routing tool it doesn't matter how it is tagged but when the lift gate and the road behind it can be passed.

Since you indirectly claimed to have all those precious years of experience it's your turn now: How would you map this?
Road:
key1=tag1
key2=tag2
key3=tag3

Lift gate:
key1=tag1
key2=tag2
key3=tag3