I agree with the OP. why should someone be "grateful" for dishonesty? I dont think they are complaining about having three weeks plus Christmas. There's was a lack of full disclosure. It was sold as a part of the package to join. Regardless of the job or industry it's not professional or transparent. It is possible they were entertaing other offers and the extra week off helped make their desicion. Probably won't matter anyway the contract is scheduled to end around Christmas next year.