Personally, I don't think they give a ****.

MB haven't split their strategies this year, but did last weekend. It wouldn't surprise me if they even wanted Hamilton to pit late for no other reason than they can say they gave both their drivers the same amount of stops and let them decide it on the track.

Hamilton obviously is confident and has clout within the team, so he can go against team orders.

I'll link this article again.

https://www.speedcafe.com/2019/07/16...stop-strategy/

Wolff confirmed that the plan was to split the strategies of the two Mercedes, although the team had expected to also bring Hamilton back into the pits at some stage.
“Obviously both of them drove a brilliant race, both of them would have deserved to win the race, and in that instance, the Safety Car swung in the favour of one driver.”
So it was meant to be Bottas with med, med, hard. Hamilton with med, hard, med. The safety car contributed significantly. Hamilton did not have to pass Bottas on the track. The supposedly inferior strategy ended up being the best one.