"It is absurd to demolish the very thing that makes this building special, to accommodate a hotel, especially one that requires significant public funding."
He suggested if the "numbers for a hotel don't work here" - referring to the public aid - "then it is the wrong project for this site."
In a counterpunch, Greg Reaves, a principal of Mosaic Development Partners, one of the companies planning to start construction on the proposed 96-room Hotel Blue in April, called the alliance's statements "inaccurate."
The public money Leech referred to was the state Redevelopment Assistance Capital Program, known as RACP.
Reaves said the original plans submitted for RACP support, - which Gov. Corbett approved for $6 million - "never included the preservation of the auditorium.
"It was always contemplated to be replaced with hotel rooms and a restaurant in its place.
"In fact, the RACP program is primarily used for economic development and we have followed those guidelines."
Reaves said Mosaic and its partner, Orens Brothers Real Estate, had investigated keeping the auditorium.
"Unfortunately, in the end, preserving the auditorium would add millions to the project's cost and result in a significant loss in annual income. We would also be preserving a venue that is obsolete by today's standards," Reaves said.
"We will honor the history of the legacy of the Blue Horizon throughout the building in a way that tells a better story about its past, and the gladiators who fought there, rather than merely preserving a quaint but nonfunctional auditorium that is well past its prime."
Preservationist Leech said he is frustrated by the "false choice that's presented between economic development and [historic] preservation.
"City officials should have the patience and backbone to tell developers that some things are too important to throw away."
Other buildings on the alliance 2013 list are: the Boyd Theater, 1910 Chestnut St.; the 19th Street Baptist Church, 1249-53 S. 19th Street; Engine 46 Firehouse, 1401 S. Water St.; Shawmont Station, 7700 Nixon St.; Robinson Store, 1020 Market St.; Haddington Historic District, bounded by 60th, Market, 61st and Chestnut streets; and Philadelphia school buildings, citywide.
On Twitter: @ValerieRussDN