Which is why it is blocked to people in the UK as they already pay the licence fee and therefore aren't allowed to be shown ads by the BBC. It's a bit of a weird situation.
They already selectively show/hide ads - for example, I'm in the Republic of Ireland, and see ads on the BBC News site.
It's a bit more complicated than that. BBC in the UK aren't allowed to operate outside their charter - they're severely restricted in how much they can compete with private commerce.
BBC Worldwide is the beeb's commercial arm, who do exactly this - outside the UK, where they're competing fairly as any other commercial venture.
So Worldwide aren't allowed to operate within the UK precisely because of the licence fee - it'd be unfair competition. It's not just because they're shown ads - it's simply because the content is produced by their commercial arm, so finds itself on the wrong side of the home/worldwide silo.
I think that because the content on the page is produced as commercial content (with the aim to make money on advertising) they can't show the content at all in the UK. (yes it's weird and it's stupid/outdated)