I hear this one a lot from the right, like a LOT. Accusations of racism right to left might equal or outnumber the reverse.
Uh huh
So, here's the thing. Humans are tribal, and that influences everyone in different ways. Structural racism impacts pretty much everyone, regardless of personal intentions or ideas or feelings, which is why it is so dangerous.
Holding leftist political ideas doesn't magically cure racism. In fact, we now understand that some of the past assimilationist or "cure racism by pulling up your bootstraps" policies advocated by the left were essentially racist, as they essentially eradicate the culture of the impacted community, or placed the blame for racism on those negatively impacted by racism. One of the main ways this manifests is with a distaste for racial integration in schools, and people sorting
That said, the flaws of the left don't hold a candle to the decades of racism by the right wing and Republicans. It was the right wing that pushed for segregation, and Republicans who decided in the 1970s (and ever since) to play up racism as an electoral strategy. This has only accelerated in the past few years, with Trump inviting white supremacists and other explicit racists into the Republican fold; and, of course, rejecting any suggestions that racism is still an issue.
We also see leftists (and most Americans, really) recognizing that structural racism, discrimination, segregation and other racial issues still persist; and that they want to actually address the issue. It is the left, not the right, that is embracing anti-racism. Sometimes this doesn't work out well (e.g. Robin DiAngelo), sometimes it does (Ibram X. Kendi).
Of course, the real reason why conservatives today try to tag the left with the "racist" label is because they realize that overt racism is no longer acceptable, and thus they try to use it as a snarl word and false accusation, in an attempt to exculpate themselves for their own moral failings, draw attention away from their own racist actions, and attack their political rivals.