Actually, being a Jew is a religion of individuality balanced with community. There is a sliding scale denoting how much individuality one is willing to let the community define which depends on denomination. But individuality is not lost in any way in Judaism. Judaism is not a totalitarian religion, and Jews do not cede power over their lives and actions to the Jewish community.
Moreover, no Jew had any right to tell another Jew how to live their lives, whether in terms of observance or anything else. We self-select into our chosen denominational communities, but those communities have no power to determine what we believe or how we live. In fact, the only point of power of the Jewish community over the individual is over converts, since the community must decide to let a convert become a Jew. But that single moment of conversion is where it begins and ends.
Individual Jews have a right to feel concern over the behavior of other Jews, just as they have a right to feel anything else they feel. But they don't have a right to dictate to fellow Jews how to live as Jews.
I know many people raised in Christian homes who have as little religious regard for or engagement with Christian holidays, most especially with Christmas, as do quite frankly the majority of Jews in America. Unaffiliated Jews are the largest number of Jews in the Diaspora. And anyone who tries to argue with a secular American Jew that going home for dinner on Passover makes them or their observance of the holiday religious will lose the argument.
Why do we as Jews think we should win the same type of argument with Christians over their own holidays? It's not a question of convincing other Jews that they should or could feel o.k. to have a tree in their homes during December. It's a question of reminding Jews that it's o.k. to find answers about December traditions within themselves without feeling like they have to defer to disapproving opinions of other Jews.
The answer to the question, "Is it right for Jews to celebrate Christmas?" should really be, "Mind your own business."