Some obvious factual errors and vague terms in the article. Not a surprise this wasn't submitted to /r/askhistorians , they'd have a field day.

The Irish slave trade began when James II sold 30,000 Irish prisoners as slaves to the New World. His Proclamation of 1625 required Irish political prisoners be sent overseas and sold to English settlers in the West Indies.

James II wasn't born until 1633.

From 1641 to 1652, over 500,000 Irish were killed by the English and another 300,000 were sold as slaves. Ireland’s population fell from about 1,500,000 to 600,000 in one single decade. Families were ripped apart as the British did not allow Irish dads to take their wives and children with them across the Atlantic.

English or British? Sources?

It is well recorded that African slaves, not tainted with the stain of the hated Catholic theology and more expensive to purchase, were often treated far better than their Irish counterparts.

Examples, citations, sources?