Most commonly it's the EU fining American tech for GDPR violations and related privacy shenanigans.
If Imgur never had UK presence, then yeah there would be no teeth. But if you're doing business in a country you can't break the law then leave and expect them to just ignore what you did during that time.
If you're the US you call planes of out the sky that have representatives and owners of the companies on them.
I'm assuming any leadership of Imgur would want to avoid going to the UK for the rest of eternity.
I would do that (after appealing) and be done with it.