The state has a century long history of answering that in the positive; under the Criminal Law Act 1977 a person agreeing with another person to do a crime is guilty of conspiracy to commit that crime[1]; section 5 talks about "the offence of conspiracy at common law" which it replaces, including when it does/doesn't apply to "conduct which tends to corrupt public morals or outrages public decency".Further back, the Offenses Against The Person act of 1861 says that encouraging, soliciting, or proposing to any person to murder another person is a misdemanour punishable by imprisonment for life[2].
AFAIK the UK doesn't ban the classic film The Towering Inferno which is about people dying in a burning tower block. The Titanic has no remaining survivors to be offended where the video here was <2 years after the Grenfell Tower fire, and your joke about the Titanic isn't mocking the dying, it's mocking the builder's hubris. So it's more about the "outraging public decency" part.
Even the most free-speechy places have arguments about what free speech is acceptable (classic example: yelling 'FIRE!' in a crowded theatre) and have ideas about free speech, with consequences.
I would rather the UK government had put that effort into earlier holding the tower management company to fixing the problems reported by the fire brigade and the Grenfell Action Group in the years before the fire, and knocking the Council for trying it silence that group for repeatedly reporting fire problems, and of course for the excellent business decisions to save money by using flammable cladding.
[1] https://www.legislation.gov.uk/ukpga/1977/45/section/1
[2] https://www.legislation.gov.uk/ukpga/Vict/24-25/100/section/...