Social media with private intelligence is the cause.
Social media is a private and state intelligence goldmine. Those with resources study what is said and craft messages to influence people's actions in real life. They then pay social media to promote these messages and then use all the data collected via rampant surveillance capitalism in order get feedback. That makes campaign successes measurable and therefore tunable. Penalties alone won't be enough to stop right wing or oligarchic movements in Europe or to protect western liberalism. A fine to an oligarch is only a declaration of war, not a meaningful check on power.
China set up the GFW because they realized that they could not subject illiterate subsistence farmer who have never left their home town to foreign interference, so they created a digital border. Yes, it also serves to put down dissent and that is bad, but it also keeps china more stable than it would be otherwise. Even Americans came around and voted to put the first brick in America's own great firewall by voting to ban TikTok. If the founders didn't bend to the current administration, then it would be banned right now for exactly the risk China saw when they implemented their own digital border.
It is not enough to fine when you have no border. Peter Thiel and his Palantir will actively work against European governments with the aid of X and Facebook by offering aid to those who can afford it with money or loyalty, which gives material power to those with selfish goals, who can use them to craft governments more amenable to their goals: Weak, divided, angry, gridlocked, and most importantly de-regulated.
Europe needs a digital border.