they are just better at hiding it

The page you're providing covers a long history. It does a great job at trying to push for a new independant party, but does a very poor job at arguing that Right and Left are the same.

Everything before "New Forms for Old Racism: Great Rebellions and the Policies to Sustain Modern Segregation" was in the early 1900's or older when things were bad as hell. Having only the last 1/3 of the article covers the present day skews the whole thing.

If you want to say right and left are the same, look at actions:

Who propped up DEI? Who dismantled it?

Which side pushed for civil rights acts? Which pushed against them?

Which side desegrated the military?

Which side preformed DOJ investigations into police departments with patterns of racial discrimination?

Which side started The My Brother’s Keeper initiative, aimed at improving outcomes for boys and young men of color.

How about The Lilly Ledbetter Fair Pay Act addressing wage discrimination, including racial pay gaps.

or The George Floyd Justice in Policing Act passed by the Democratic House in 2020 (though blocked in the Senate).

or The John Lewis Voting Rights Advancement Act restoring protections against racial voter suppression.

You can find what feels like an unending list of democrat initiatives that dampen racsim, flipping to the republicans you can find a handfull at best.