Elon is not acting alone here.

He is acting as a direct instrument of the new US National Security Strategy, which designates the EU institutions as a national security threat to The USA.

The larger issues facing Europe include activities of the
European Union and other transnational bodies that undermine political liberty and
sovereignty, migration policies that are transforming the continent and creating
strife, censorship of free speech and suppression of political opposition, cratering
birthrates, and loss of national identities and self-confidence.

The Granite Act in the US will allow US citizens to sue EU institutions for censorship in US courts with damages out of EU funds held in the US.
This is similar treatment to rogue states and terrorist organisations.
EU officials will be sanctioned like Francesca Albanese & other ICC officials have been.

The Trump Administration has made it a national security priority to turn Europe from its current self-destructive course and reform or destroy transnational organisations that infringe US interests.