I think there’s been some general confusion as to why we see Sarek showing no apparent signs of disappoint with Michael joining Starfleet, especially since he disowned Spock and wasn’t on speaking terms with him for 18 years when he enlisted. It is pretty weird! Discovery even explicitly shows us that he not only was okay with the idea of Michael in Starfleet but he pushed her into joining.
The disparity between the two reactions hasn’t been explained yet in canon but I’ve got some ideas.
The scene that shows Sarek personally escorting Michael onto the Shenzhou tells us a lot. And one of the most important details I think is that we know that Michael doesn’t want to join Starfleet. From the second she’s aboard the ship she comes off a little cold, and Sarek quickly reprimands her for the behavior which is easily explained as her lack of association with humans.
At this point in her life I’m assuming Michael is 25 (given her actress’ age), and by the looks of her during the attack at the learning center we can guess that she’s been Sareks ward for at most 15 or so years. In those many years on Vulcan she’s clearly assimilated pretty deeply in the Vulcan way of life as we can see with how out of place she is on the Shenzhou at first.
Michael even tells Philippa that she never planned to be apart of Starfleet and her plans were to continue living and working with Vulcans.
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P: “Is this vessel not up to your standards?”
M: “I have no standards when it comes to this ship. It was always my intention to join the Vulcan expeditionary group.”
—
Okay then so from all of this we can infer that Michael was perfectly content being estranged from human kind and continuing life with Vulcans and that she only changed her life plan to appease Sarek. She trusts his judgment and pretty much allows him to micromanage her life even though she’s in her mid twenties.
And we know that Sarek personally arranged for Michaels appointment to the Shenzhou.
Okay then so why does he go out of his way to arrange this set up at Starfleet with Michael and then turns around and completely condemns Spock for enlisting?
Here’s what I think.
(Cont…)
Starfleet is a diverse environment with aliens from various backgrounds, but nonetheless, it is primarily human. As we can see from these scenes, Michael is pretty deeply assimilated as a Vulcan, and Sarek most likely pushes her towards Starfleet because he wants her to reconnect with her human heritage.
Clearly Sarek doesn’t have a problem with Starfleet as an institution, as an ambassador it’s easy to assume that he often works closely with them. He doesn’t have a problem with Humans he’s married to one, he’s raised a human child and a half human child, he’s the ambassador to earth, he works alongside them.
What he has a problem with is Spock’s rebellion. He holds Spock up to a higher standard because he is Vulcan and has from a young age committed himself to strictly following the Vulcan way.
While he did raise Michael similarly, he never held her up to this impossible Standard because to him she biologically could never be Vulcan. He’s more lenient towards her and acts more tender towards her for similar reasons as to why he acts tenderly towards Amanda. They’re both dedicated to the Vulcan way of life but he knows there’s only so much they can do.
When Spock joined Starfleet it was a clear rebellion from everything Sarek expected of his son. It’s Spock trying to reconcile his human side with his Vulcan side, and Sarek probably reacts so negatively because he interprets this as a rejection of the Surakian way. And he realizes that he has no children left to follow those teachings. Sybok ran off to be a space hippie, he pushed Michael towards Starfleet and Humanity, and he inadvertently pushed Spock in the same way.
For Michael Starfleet is conformity to Sareks wishes, and for Spock Starfleet is rebellion from it.
Do I think his actions are okay at all?? nah I think he’s being a dick to his son and he’s showing some signs of favoritism towards his daughter. This is just what I’m thinking is going on with the guy and why he acts the way he does.
Hope some of ya’ll think I’m rambling is interesting or hopefully not completely off the mark.