I think there was an effort in the past to make sure it’s a family show and disconnect The Doctor from the more mature parts of the whoniverse. Maybe the changes in production and, maybe, the realization adults are too obsessed with it create new avenues for money making creativity.
Uh… who ever thought any part of the entirety of the series was?
It’s a family show so it’s always kept ‘kid friendly’, but that doesn’t mean it can’t be scary. I remember watching as a kid with a pillow to hide behind when the monsters came.
It was originally an edutainment show for history and science, and had a strict policy of no kissing, no bad language, and no bloody violence. They still keep to the last two.
You could be fooled by a lot of the Matt Smith episodes.