There is a big difference between voting for someone who was a definite PED drug user (Bonds, Clemons, Manny, A-Rod, Mcgwire, Palmerio) versus voting for someone who may (or may not) have used PEDs (Piazza, Bagwell, Henderson). The HOF will be a disgrace if they let in the former group (definite drug users). The latter group is an unknown--the result of imperfect information.
Sure, we have imperfect information, that is the reality of life, and so, yes, drug users will get into the HOF. But there is a big difference between that and voting for players who were definite juicers.
Once you let definite juicers into the HOF, the standards (and ideals) of sportsmanship, fair play, etc., will be greatly diminished throughout our society. The HOF has a responsibility to not let that happen.