Racism (if done in a “smart” way) is impossible to prove. Does that mean that we should then not try to detect it or speak up against it, simply because we will

Racism (if done in a “smart” way) is impossible to prove. Does that mean that we should then not try to detect it or speak up against it, simply because we will never be able to objectively back up our claims? And if yes, then does that not strengthen even more the case (and benefits) for being a racist? Also I believe it’s disingenuous to treat racism as such a concrete, objective term. Maybe they are preying on me (and other people like me, which there are objectively many) simply because I’m the weak link in the system? But if my weakness stems from me being an immigrant (because I have no safety net, no family around me or a shoulder to cry on, because I don’t know the system well enough and thus I’m more likely to accept injustice and stay quiet) is that “racism”? Or “prejudice”?