[defrost]

The UK, under a monarch, abolished slavery and set the Royal Navy to blockade slave ships.

Meanwhile, the USofA pre civil war under a President with no offical monarch (other than the Little King for a term arrangement) had extensive slave plantations.

[crowselect]

The UK abolished slavery by an act of parliament. A parliamentary monarchy is a historical quirk that does not need the monarchy to function.

[defrost]

Good that you agree slavery was abolished by a country with a monarch ... you skipped over the second point; the country most associated with industrial scale slavery in the world had no monarch.

It's a loose correlation you're making here, very much a "let's build this skyscraper with wet noodles instead of steel" approach.

[crowselect]

Slavery was “abolished” in the UK while that same nation continued to traffic and profit from enslavement for quite a long time it’s “abolition”. Is your point that monarchy is good, or that slavery is associated with all forms of government?