To clarify - you're saying that 10 more hours of a cat dancing to techno was not at all an issue for Google to host but that a conference about media censorship was the straw that broke the camel's back?
Also, platforms are famously not accountable for what users upload - that's what makes them platforms and not editors.
legally platforms are often not accountable for what users upload (sec 230), but over the past several years journalists and politicians have been demanding that platforms remove content that said journo-politicians don't like, so in a sense the platforms are made to be accountable - do it or else regulation
Also, platforms are famously not accountable for what users upload - that's what makes them platforms and not editors.