If so, how is someone being racially discriminated against by IQ tests continuing to be used?

See again, my example of the 2020 grading controversy, where students were marked below their expected grades based on an algorithm that used average demographic SAT scores. 36% of GCSE students were graded significantly lower than they should’ve been. You wanna guess the racial make-up of schools hit harshest by this?

what has genetics discarded that IQ tests haven’t?

Well for starters eugenics has been rejected in the mainstream consensus of geneticists. Their crackpot theories are rejected and their racism is unsupported by their academic peers. James Watson publicly expressing his bigoted views on race and IQ resulted in a barrage of complaints by his peers in the field of genetics.

On the other hand in psychometrics:

Charles Murray, (to name but one prominent eugenicist psychometrician) continues to publish his works tying IQ to race on a number of journals, is broadcasted on a variety of publications, and his works (despite not holding up to much scientific scrutiny) continue to be cited in studies into IQ.

Richard Lynn and J Philippe Rushton, are two prominent professors of psychology who are very outspoken about IQ being connected primarily to race. They are in charge of the pioneer fund, a eugenics institute. Rushton has argued in favour of phrenology.

The American Psychological Association was still publishing pro-eugenics articles as recently as 2005.

That’s the difference. Genetics has discarded its eugenicists, psychometrics has kept them.

what elements remains in psychometry that causes harm where IQ tests are still used?

The main changes on how IQ is measured have been to account for the Flynn effect. There has been no attempt to correct the fundamental flaw in how IQ tests work, ie their conception of intelligence revolves around the pet theories of some 1920’s eugenicists.