Philadelphia’s two largest newspapers will lose 40 more newsroom employees this month, prompting union leaders Thursday to accuse management of bungling a tablet computer launch, censoring stories and deriding print newspapers as “legacy products.’’

The losses are just the latest setback for staffers, who have gone through repeated rounds of cutbacks and might soon have their fifth owner in six years.

A group of local powerbrokers and philanthropists hopes to buy Philadelphia Media Network from the New York hedge funds that took control after a 2010 bankruptcy auction. The sale price has plummeted from $515 million in 2006 to $139 million in 2009 to perhaps less than $70 million this year.

The hedge funds installed former Newsweek.com executive Greg Osberg as publisher in late 2010. The guild attacked his leadership in a sharply worded memo Thursday.

“Perhaps instead of killing stories he didn’t like about the sale of the company and trying to be seen as some sort of digital visionary by holding press conferences at the Academy of Natural Sciences, … creating a poorly launched tablet and worrying about apps that make a few dollars, Osberg should be focused on properly staffing the newspapers,’’ the local Newspaper Guild said in a memo Thursday.

Osberg didn’t immediately return a message. Spokesman Mark Block defended the tablet launch but said the company won’t debate the criticisms of management in public.

“Neither the region nor the company would be well served debating the guild’s comments about leadership and products,’’ Block said.

According to the union, 21 people are taking buyouts and 19 full- and part-time editorial workers will be laid off by March 31. The Inquirer’s Pulitzer Prize-winning cartoonist, Tony Auth, is among them.