Why did Canada, US and UK attempt to defeat a motion for the elimination of racism, racial discrimination, xenophobia and related intolerance at the United Nations?

In March a UN Core Group on Sri Lanka – including the United Kingdom, Canada, Germany, North Macedonia, and Montenegro – did not stand by the numerous victims of abuses by calling for renewed Human Rights Council action. In its statement, the Core Group merely “encourage[d] the government of Sri Lanka to continue cooperation and dialogue”. While Sri Lanka rejected this motion, it was adopted by the UNHCR with a majority vote.

Full text of the motion:
https://digitallibrary.un.org/record/3896183?ln=en

In April, Federal Liberals have used an unpopular tool to limit time for debate in the House of Commons on a bill that would harmonize Canada’s laws with the United Nations Declaration on the Rights of Indigenous Peoples. The Liberals successfully passed a motion to impose closure on the opening round of debate on Bill C-15 in order to put it to a vote and move it along to a Commons committee for further scrutiny. Bill C-15 represents the third attempt to have Parliament approve implementation of the UN declaration in Canada. The UN declaration, which Canada endorsed in 2010, affirms the rights of Indigenous Peoples to self-determination and to their language, culture and traditional lands. It also spells out the need for free, prior and informed consent from Indigenous Peoples on anything that infringes on their lands or rights.