The news the BBC didn't think relevant to their PMQs coverage

Earlier today I blogged about today's PMQs and why the only background passage was this:

'The cables, obtained by whistleblowing website Wikileaks, also include a string of revelations about Bank of England governor Mervyn King's concern about Mr Cameron and Chancellor George Osborne's lack of experience ahead of May's general election.'

The Mail however reports:
'Gordon Brown falsely told President Obama that Britain could not commit extra troops to Afghanistan, WikiLeaks revealed last night.

But U.S. diplomats made their own investigations and discovered up to 2,000 troops would have been available as relations with the UK government became strained.

American attempts to go behind Downing Street's back and check what they were being told suggest the Obama administration did not trust Mr Brown.

...

U.S. ambassador Louis Susman warned that the Prime Minister was a ditherer who would attempt to use her (Hilary Clinton's) visit to bolster his general election campaign.'

So allegations that Gordon Brown lied and was described as a ditherer are not worth the BBC's time but the David Cameron and George Osborne allegations were; why the discrepancy?