Flirting and innuendo have nothing to do with celibacy.
And what does it matter, as long as we don't have anything on the screen that takes it into adult territory?
It seems there is a tradition of getting each Doctor to kiss each companion, so that kind of has to stay now.
It's a shame that people seem to think Moffatt can't write believable relationships and can only use one-liners for conversation... There are far more characters he has written than those people use as examples, but they are mostly ignored, as they don't hold up the argument. Yes, some characters Moff has over-written, but there are many more he hasn't. Not every single female character Moff writes has a flirty relationship with ihm, but those who do stick in the mind. It's confirmation bias.
One more thing, the show is not for us, it's for the next generations of Who fans. we should not (and I'm glad we don't) dictate what should and shouldn't happen in it. If many people here had their way, it would return to the classic Who format, and would disappear of the telly quick as a flash. Audiences nowadays just would not watch it - it would be dry and unpalatable to the general audience - and whether you like it or not, that is who the show is aimed at.
Why go back, in a show that's all about moving forward?