News items are often unique, and totally irreplaceable: Dud and Pete at least have had a selection of their output preserved, and scripts are surely available for other material.
Furthermore, the fact that clearances from the archive concentrated on light entertainment and drama, leaving news coverage behind, owes much to the short-sighted behaviour by the likes of Equity on behalf of their artists. The union limited repeats of older material in favour of new productions.
Once overseas sales had been exhausted by the BBC, and with little chance of it being re-screened, much material became unusable and archiving a drain on the licence payer's money. Utilising the space for news makes commercial sense under the circumstances.
Had Equity undertaken to finance the archiving of the material in conjunction with the BBC, older programmes might still have been with us yet.
Only the unforeseen development of domestic-video revealed that this material had further commercial exploitation potential, by which time it was too late.