After doing some research I now understand why Zuckerberg has gone all in with Trump.

Zuckerberg wants Trump to have Congress enact legislation that will punish foreign govts if they imposing content restrictions/limitations and/or user data privacy requirements on U.S.-based social media platforms.

Meta (and other platforms) is facing serious financial disruption in various foreign nations unless something is done to stop the mandates those countries are imposing on social media companies. 

If the actions of those nations are left unchecked, Meta's annual revenue loss will likely wind up being in the tens of billions of dollars. Mark wants Trump and Republican in Congress to rescue Meta from those very significant losses.