Everyone is aware of Watson's contributions (though there is of course ample evidence that he stole a lot of the work from Rosalind Franklin and gave her no credit for it, then said things like "of course Franklin couldn't envision the structure of DNA because jewish women can't see in 3D - he said this in front of a preeminent female jewish structural biologist too). The discredit isn't against his scientific achievements, it's against his racist-ass opinions. That's why people don't invite him to talks much anymore, because he just goes and says made up racist shit.