His Louis Saha-like disruption in the last two weeks while his route to Chelsea was blocked was not the sort of loyalty they had hoped for.
Charlton suspected the fingerprints of mischievous agents on his actions and were angered, but they decided that reacting directly would be futile and chose the pragmatic approach.
Curbishley said: "I've been unhappy with the way it's been conducted over the last few weeks and that includes a lot of people, not just Parker. But that's football and that's life."
The Charlton manager thought last summer he had convinced Parker to stay for at least a season when he signed a new five-year contract.
But he had seen the midfielder's departure on the horizon and Matt Holland's arrival last June was designed to cover that eventuality.
The former Ipswich captain can adopt his favoured central position in Parker's place and the domino effect of the transfer is also good news for Claus Jensen, who is looking for a new contract but had fallen down the pecking order.
It may not seem like it now, but it could also be a blessing in disguise.
Fans will regret the loss of Lambeth-born Parker, who they had adopted as one of their own, and the drive, tenacity and skill he brought to the team.
But his departure makes the side no less resilient, a key Charlton characteristic, and may establish the club closer to the Premiership's elite in the long-term.
They are fourth in the table now and set for a fantastic season but further investment will be needed to sustain similar success in the future.
A transfer fund of £10m will go a long way in the summer as Charlton will be one of only half a dozen clubs in England with that sort of money to spend.
Curbishley's transfer record suggests he will not gamble it away and there is a good chance he may be able to wash away the bad taste left by Parker with two or three signings who are just as good.
