The United States government just sold over 200 people, without trial, into slavery in El Salvador. And the US explicitly allows slavery as part of its own prison system. The US has a large number of legal slaves.

They overthrew Gaddafi when he was the only thing preventing slavery from returning, and the allies of the West now have open slave markets in Libya.

Houthis did not reinstate slavery. The "legitimate" Yemeni government that the Houthis are rebelling against reinstituted slavery

They're not threatening global trade, they're fulfilling their obligation under international law to prevent genocide by blocking ships of countries that are aiding genocide.

What lead them to be on position to be able to do such a thing?

Who helped to stabilise the previous gov & infrastructure (hospitals) ... and stopped overnight destabilising the country early pre-covid?

The houthis aren't exactly the best representatives of the movement but still, this issue would be better solved by stopping arms shipments to israel and pushing them to a ceasefire towards a permanent peace. The houthis have shown that they will stop there attacks when the bombs stop dropping on gaza with this last ceasefire.

These strikes don't do shit besides hardening the antagonism against the west in Yemen. Ask Saudi Arabia, you can't take out the houthis with bombs. This is just a way for trump to flex his arms and act like a tough guy.