All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Festival are part of religious legislations; Allaah Say (what means): {To each of you We prescribed a law (legislation) and a method.} [Quran 5:48]. Therefore, a Muslim is not allowed to adopt the festivals of non Muslims as his festivals.
Anas narrated that when the Prophet, arrived to Al-Madeenah, people had two days which they used to celebrate, so he inquired: "What are these two days" People said: 'These are two days we used to celebrate during our pre-Islamic era', Thereupon, he said: "Indeed, Allaah Has replaced them with two days that are better than them; 'Eed Al-Adh-Ha and 'Eed Al-Fitr" [Abu Daawood].
Scholars are not allowed to remain silent regarding this evil. Every person is obliged to forbid evil according to his/her ability. Abu Sa`eed Al-Khudri reported that the Messenger of Allaah said, "Whoever amongst you sees an evil, he must change it with his hand (physically); if he is unable to do so, then with his tongue (speak out); and if he is unable to do so, then (he should detest it) with his heart; and this is the weakest form of Faith". [Muslim].
Allaah Knows best.