There are several published statements, not just the one you posted. A letter from the First Presidency in 1968 (I believe?) was even more definitive. Additionally, there is no evidence that the Prophet Joseph Smith denied the priesthood to black men that I know of. If you'd said that, we'd be in perfect agreement. However, your assertion requires all to accept that we know the origination, the Church leaders knew the origination, then covered it up until forced to change policy. That isn't proven, nor do many accept it.
This is where we get into HUGE issues, in my opinion, when discussing Church history. We can discuss the facts as we know them and agree. We can even make assumptions based on those facts and agree or disagree. However, when one side starts assigning nefarious intent as a definitive and using that in an attempt to then assert nefarious intent BY OTHERS on completely different topics, the discussion stops being factual and becomes antagonistic.
You might even be right on your premise, even though there is no evidence that I know to prove it, but your assertion doesn't support your claims in other areas.