I see quite a few posts floating around expressing upset at Mycroft being “straight” - it’s gone 1am here, I’m sure this is something which will be mulled and meta’d over a lot. So just my initial twopence worth:
I liked the flirting from Lady Smallwood. I liked the suggestion in TST that they had a past together, but I definitely didn’t see this coming and I laughed out loud at Mycroft’s adorable confusion. I thought it was nice to have an older female character being shown in that light, and it not being a joke - she’s a powerful woman, and she’s calling the shots. Mycroft Holmes, potential toy boy. Far twistier than any secret siblings.
Yes in probably 98% of fic where sex or relationships are explored, Mycroft is characterised as gay or asexual, so a lot of folk in fandom might see the way things have gone as contrary to what they would have chosen. I’ve never made a secret that I ship Mycroft with basically everyone, so perhaps I just don’t find it quite so shocking.
I don’t know. It seems patronising as I write it, but I just want to put out there that Mycroft’s taking the card doesn’t mean your preferred headcanon has to be destroyed. Why would taking the card make him straight? This from a fandom that has worked so hard to make a case for John, a married man with a series of former girlfriends, as being bi!
For the show canon, we’ve not seen Mycroft’s personal relationships at all outside of the “goldfish” conversation. So what’s to say he’s not primarily gay but open to experimentation, or grey/demi sexual and he respects Lady Smallwood’s intellect, or just basically flexible. Or maybe he misunderstands the whole thing and is just intrigued at what she keeps in her drinks cabinet. Who knows. But I don’t see it as a heterosexual conspiracy.