This is an unsustainable position that will simply retard free trade, cause companies to refuse to hire people outside their home country, to the loss of everyone. It also breaks the moment two different countries decide they want mutually contradictory things (which happens all the time), and would result in people being forced to use non-innovative and poorly executing local clone companies instead of the best available services.
Because both Facebook and Giphy are active in the UK market.
If they don't want to be subject to UK regulation then they're free to stop doing business in the UK.