The Baseball Hall of Fame needs Mike Piazza far more than Piazza needs the Hall of Fame.
Mike Piazza is the best offensive catcher of all time. The numbers speak for themselves on this matter. The only thing that can change this fact is the birth of a better hitting catcher. Apart from the pure stats, Piazza is adored by millions of fans on both coasts. Mets fans will love him forever for his game-winning homer in the first game played in New York after 9/11, but that was only the peak of his achievements. As far as the game of baseball is concerned, the Hall of Fame can't give Piazza anything he doesn't already have.
The Baseball Hall of Fame, on the other hand, is little more than an idea of a ghost of a myth. The Hall's site was chosen based on a risible fabrication about the game's origins. Like many unimportant things, it believes it is extremely important, but that does not make it so. The Piazza snub underscores this fact.
Many Hall of Fame voters failed to vote for the players like Piazza, or for other players whose stats dictate a Hall-worthy career, because of misdeeds real, perceived, or imagined. For Piazza, the case against him is essentially Guilt By Osmosis, and the overlooking of him far more egregious, since he played a position where the greats are few and far between.
In failing to select Piazza, voters misunderstand what the Hall should attempt to do and their role in that process. The same goes for those who voted for some of these players but not others. These voters believe their job is pass judgment on an era, parse out the sinners from the saints. They see themselves as gatekeepers who will allow some to pass and make others wait, perhaps forever.
There is a tone of the wronged in these pronunciations, suggesting voters see their selections and exclusions primarily as a way to grind axes. This was reflected in the words of Ken Burns, self-styled baseball documentarian, who said the goal of his ballot, if he had one, would be to make sure players like Piazza "suffer for a while." The idea that it's a voter's duty to punish some players could spring from a sense of justice, from the idea that "juicers" took jobs from equally talented but "honest players. It could also speak to guilty consciences, the reflection of writers who covered the Steroid Era and let it happen under their noses without sparing one word to tut-tut it at the time.
Hall of Fame ballots aren't supposed to be revenge fantasies, or acts of redemption for unnamed quadruple-A players or the voters' own professional failings. Baseball history happened regardless of their hurt feelings. PEDs were used, by some of the best players, some of the worst, and some in the great middle.
Parsing out who did what and when is not the voters' job. If it is, they'll have to go back and do the same for the many players already enshrined who availed themselves of speed in the 1960s, 1970s, and 1980s--a substance that was more illegal when those players used it than most PEDs were in the 1990s and early 2000s. They'll have to reexamine the first classes of the Hall of Fame, which were comprised solely of players who possessed the unfair advantage of not having to compete against peers whose skin was darker than theirs.
For the Hall to have any meaning whatsoever, it can't pass judgment on an era and its misdeeds. It must simply reflect it. The Hall is not a fortress that needs defending from an army of scribes. It's a museum, and worthy museums don't leave out entire decades because they don't like them. Imagine a Civil War documentary without General Sherman, erased from the record because Ken Burns thought the march on Atlanta was really uncool.
The Hall means something only insofar as it reflects the realities of the entire history of the game. It has made occasional strides to do this, such as enshrining Negro League greats who excelled outside of MLB's confines. After decades of ignoring these players, the Hall and its voters realized that to exclude them meant the Hall was incomplete. It was a move that, at its core, was meant not to elevate the players, but to elevate the Hall.
So it will be with Piazza. The Hall of Fame cannot validate his career, but his exclusion invalidates the Hall.