It is obvious that Ali can get away with asserting racist things because he is black, and most charges of racism are used to silence whites opposed to the left's agenda, not black sports heroes.
What's clear from listening to the interview is that Ali didn't "get away with" what he said in the only sense anyone ever does: not being challenged on it.
Not all racism requires an assertion of racial superiority. That one wants the law to distinguish between one race and another is racist in and of itself and that due to the idea that race-ism is to advocate policies and laws in which a person is processed primarily on the basis of their race.
Racism is a motive or set of motives. As such, it cannot be objectively defined in terms of actions, even if certain actions seem to be typical of it. The motives of racism include a desire to promote the social, political, economic, and/or cultural supremacy of one race over another, or to preserve racial purity. Anything done from these motives, and any belief arising from and empowered by these motives, is racist. Anything that does not include these motives is not.
Affirmative action is racism.
Bussing for school integration is racism.
As neither of these is undertaken from the motives of racism, no, they are not.
A person choosing to marry someone of their own race is NOT racism.
A person prefering their own kind to socialize is NOT racism.
A person choosing to marry someone who
happens to be of their own race is not racism, but a person choosing
a priori "I will only marry someone of my own race" is. It's motivated by a desire to preserve racial purity.
A member of a race organizing to protect their won interest is not racism.
By that logic, the secession of the South, designed to preserve the "won interest" of rich white people in owning black slaves, was not racist. By that logic, Jim Crow, designed to preserve the "won interest" of whites enjoying a superior social position, was not racist.
The hypocrisy of the left is that they will assert the last three are racist only when a white person does it. And that is why the term racism is losing both its clear meaning and its sting.
What's absolutely obvious here is that you are attempting to define and bracket the concept of racism so that many things which obviously are racist become non-racist (and justifiable), while many attempts to rectify racism or its lingering effects become themselves racist and so open to condemnation.
It's quite transparent.