It is their choice, if you want you can do to. I am a Muslim and guess what? My mother is a Christian and I was celebrating Christmas with her since I was born until present, but still I do not believe in Christmas, it's a matter of faith. What matters as a Muslim is that as long as you don't believe in Christmas while you celebrate it just for fun, then everything should be fine. But it is much preferable if you don't celebrate that, because you may fall into shirk, you never know what's gonna happen, so that's why we have Minor Festival and Festival of Sacrifice, because they are original and its creator is God Himself, because He created those festivals for us, and they are in the same time 100% true. First of, "Festival of Sacrifice" is when a prophet I guess, wanted to sacrifice his own son to needy people and God has sent a sheep in order to sacrifice and so, his son was saved, and that's the day when the "Festival of Sacrifice" is born, and it is mentioned in Quran already. And "Minor Festival" is celebrated after the end of Ramadan, next day after the end of Ramadan if I'm not mistaken..., so in these two festivals it is even obligatory to believe in it. But have you heard about Christmas in Quran? No, because it says in Quran that God did not taken any son for Himself. You can celebrate whatever you want, but what matters if you don't believe in those innovated festivals, that's all what it matters. Where you raised as a Christian, and then converted to Islam later? Sometimes you may celebrate other festivals just only to make new friends or just to show that you can be friendly person, or sociable. If you don't want to celebrate, it's up to you, if you want to celebrate it, it's also up to you, so it's your personal decision and choice, you have free will. Myself, I celebrate it, just to show some respect for my mother because she gives me gifts on Christmas, and I want to show her some love, but that doesn't mean I should believe that it is Jesus's birthday or it is you know what. Christians also agreed that neither in Bible mentioned the exact date of Jesus's birthday, it only says something in winter it is his birthday, that's it. Myself I don't believe neither in this, because Ixdo not find anywhere in Quran that says like what in Bible says. Hopefully I have said everything correct, if Ixhaven't said, please just correct me. Some they celebrate it just because it is fun, because they were raised as Christians, then converted to aisle,(don't know for sure) and they want to only have some respect for others's festivals without telling them anything.[/ QUOTE)
Of course you are free to do what you want. I am free to do what I want too, that's why I choose not to celebrate Christmas for the reason I already mentioned.
You will answer Allah for your deeds. I will answer Allah for my deeds. I leave it at that.