May the peace and blessings be upon the beloved, best of creation, the light of all times, Sayyidina Muhammed, and upon his family and companions.
It doesn't matter even if the majority of people celebrating Christmas are atheists. The issue is whether its still practised as a religious thing by some, and what it is associated with. There still are many Christians that take Christmas as a religious celebration. Even if you ask a 5 year old kid, "what is Christmas?", he will say "when Jesus was born, and he was son of God". So its haram. But if in 1000 years time, if no one is Christian, and people don't associate Christmas with any religion, and its just a cultural thing, then it could be different case.
"Besides, Christianity is probably the last thing on the minds of many of the people who celebrate Christmas each year. Christmas is wildly popular in Japan and China even though, Christianity is merely the minority religion in both countries."
The Prophet forbade prostration to people, because he feared that it would lead to shirk, as people would become closer to doing shirk. That's how Islam has been able to be fiercely monotheistic, by clearing itself of foreign elements.
Also these countries are following America and Europe in Christmas, and who are they (and the atheists etc) following or imitating in celebrating Christmas? Well they're imitating the current Christians. So there you have it in another way, Christmas being celebrated by misguided Muslims would fulfill the Hadith about imitating the non-Muslims.
The Prophetic example is the best. He didn't have Christmas trees, nor did anything that was tied to another religion or non-Muslims uniquely. He didn't say "we need to have some pictures of the Quraysh idols so that we can show intercommunity faith-building" or any of that nonsense used to justify haram practices.
The article of Syazwan has got a lot of publicity due to the following reasons:
1) lack of knowledge amongst people
2) the want of people to follow their desires and to rationalise their desires
3) it favours non-Muslims,
Thus you see many non-Muslims spreading and promoting the article.
I also am not saying that Syazwan can't give his opinion in a public platform. I'm just saying that Islamically he shouldn't, because he's not qualified, and the Prophet warned against it, although no one will force anything upon Syazwan. And readers should realise that he's not an authority in the matter.
The fatwās of unqualified individuals are considered “null and void,” according to Sayyidina Umar (RA), second caliph of the Prophet.
I leave you with a beautiful and intelligent Hadith that is being fulfilled now as we speak and reflect upon what has happened and is happening, and how the Prophet viewed people who give opinions without being Islamic scholars:
May Allah Most High guide us to the straight path, ameen
"A criticism of Islamic practices in Malaysia" by Syazwan Zainal