I mean, to be fair, he is sometimes socially inappropriate, and misses social cues, and can come across as horribly rude when he’s focussed on a case, or intent on getting evidence of a confession from someone. John does let him know when he’s over-stepping what is considered socially appropriate (there’s a whole segment at the beginning of TRF specifically about this). So, I don’t object to the idea of John being a bit of a bridge to the world for Sherlock.
The way Sherlock’s brain works is different from the average, and that does set him apart. Sometimes it’s a huge advantage, other times, and in other ways it’s a disadvantage. A life partner can help ease one’s passage through the world, but that should always be coming from a place of unconditional love, and of assuming competence, and of seeing the person you love as a fully-formed adult human being.
What I object to is the way that Gatiss (more so than Moffat) seems to write Sherlock as neurodivergent (specifically somewhere on the autism spectrum), but at the same time doesn’t seem to respect it. I mean they play fast and light with the concept throughout the series. It’s a very uneven and unrealistic take on it, in many ways. But, Sherlock does have more autistic traits in Gatiss-penned episodes than in any written by Moffat or Thompson. In fact John and Lestrade even make conjecture on a diagnosis in tHoB, with Lestrade landing on ‘Aspergers’. So, I think that Sherlock being neurodivergent is in the back of Gatiss’ head when he’s crafting the character, and so I strongly object to him saying that Sherlock is being ‘trained’ by John. It hints at old-school Applied Behavioural Analysis (ABA), which is such a sore spot for most Autistics, because it overrides the person’s consent, their right to say no (in fact it punishes them for saying no, or refusing compliance), and it is essentially very similar to dog training. It also leads to a myriad of psychological problems later on in life. And I say this as a former ABA practitioner who actually quit for this specific reason. It’s abuse.
You don’t want that kind of relationship with a friend, and certainly not a life partner. It’s not healthy. It doesn’t help that the Colbert clip we got from TST also has John and Lestrade infantalising Sherlock for his neurodivergence. I have an ill feeling about the entire episode by now, and I hope that I’m proven wrong and it all turns out alright, but damn, it isn’t looking good.