If you read the article it's pretty clear that the shift isn't what people are mad at. It's that it didn't happen sooner, perpetuating the suffering of millions by continuing US policy (including Trump's legislation since 2017) for years at the expense of the entire population of Cuba. Not to mention in violation of International Law.

"It is important to note that the economic blockade and much of the dozen coercive measures that have been put into effect since 2017 remain in force to strengthen it, with full extraterritorial effect and in violation of international law and human rights of all Cubans," the ministry added

Many progressives welcomed Biden's shift. Congresswoman Nydia Velázquez (D-N.Y.) said in a statement that Cuba's SSOT designation "has only worsened life for the Cuban people without advancing U.S. interests" and "has made it harder for Cubans to access humanitarian aid, banking services, and the ability to travel abroad." "It has also deepened food and medicine shortages and worsened the island's energy crisis, especially after Hurricane Rafael," she added. "These hardships have driven an unprecedented wave of migration, leading to the largest exodus in Cuba's history."

Alex Main, director of international policy at the Center for Economic and Policy Research, said Tuesday that "while this decision, which comes years after 80 members of Congress urged Biden to reverse Trump's 'total pressure' approach should have been made long ago, it is better late than never."

David Adler, the co-general coordinator at Progressive International, called the delisting "far too little, far too late." "POTUS removing Cuba's SSOT designation in the final days of his presidency only means one thing: He knew—from day one—that the designation was simply an excuse to punish the Cuban people," Adler added. "But he maintained it anyway. Sickening."

The peace group CodePink released a statement welcoming Biden's shift, but adding that "it is unacceptable that it took this administration four years to address these injustices." "President Biden made the inhumane decision every single day to not alleviate the suffering of millions of Cubans by keeping this designation in place," the group added. "As we mark this overdue progress, we can only hope that the Trump administration does not reverse these crucial steps towards justice and diplomacy."