It's not their decision.
You could of-course lobby your MP to get it changed, but I imagine there would be substantial opposition from both supporters and opponents of public media services to allowing BBC to run commercial services in the UK.
If BBC Worldwide had not lost that £80m, how much in additional funds could have been offset against the license fee that UK people pay?
The majority of the operation is a taxpayer-funded public broadcaster with a remit to produce high quality programming for free; but there's a unit called BBC Worldwide whose job it is to battle it out in the red-in-tooth-and-claw world of commercial TV programming, selling BBC programmes overseas and minting money that can then be used to subsidize the public broadcasting component.
That would imply that BBC Worldwide profits do impact the license fee (assuming the BBC don't just spend the profits, but use it to drive down license fee costs).
I thought the primary reason for it not running commercial services was so that its integrity as an independent source of news and culture wasn't compromised. So surely by running anything commercial, it is potentially compromised.
You can already see that by the type of programmes that get made these days. It's clear much of it is made to sell to the rest of the world, rather than just for a UK audience.
IMHO this is just breaking the net, and blatantly weird.