Sorry? What's all this 'conscience' nonsense?
It's about terms and conditions of booking.
You book, you read the small print, you pay your deposit.
If you then decide to break the contract, you suffer any consequencies.
If you're that concerned about the potential need to cancel later, you either mitigate your loss by buying insurance so that it is someone else's risk.
Or you take the risk yourself.
This situation ain't rocket science.
And neither is it anything Thomas Cook have done.