Stats are too intertwined and interdependant; purging stats would make a joke of all stats. As TR said, there's the integration issue. Then there's expansion --- would there be a factor for those years?
Even limiting it to steroid users (ignoring that we're deciding who used without proof -- they weren't tested, we'd need confessions ar credible witnesses), shall we then amend the pitcher's stats that threw to them? Their ERA should go down. (Even Lima when he admitted to grooving a few to Sosa in '98?
) How many of their hr were "steroid-induced"? All? 50%? 75%? 30%? Would Runs Scored or RBIs for teammates be impacted?
This whole issue could be derailed or distracted by getting all concerned about what happened in the past. Zero tolerance NOW will get the vital message across.