not at all. can you explain why you think its so wrong UZ?
would christians or jews be sinning if they wished us Eid Mubarak? i highly doubt it.
going to church with them and praying along with them is not allowed, sure, thats practicing their religion, but wishing them to have a happy day while they celebrate their religion? NOT wrong. its called being neighbourly and friendly and partaking in someone else’s khushi. your bar/drink analogy is incorrect. drinking is forbidden in islam, wishing someone have a happy holiday isn’t.
this is where things start going into extremist-land, imho. one day you don’t wish them merry christmas because its “wrong”, the next you stop speaking to them because its “wrong”, and then what? you wage war on them because their beliefs are “wrong”? 
and forget christmas for a second, what about within islam? what if its muharram and you are a sunni. would you acknowledge it? no one’s asking you to do maatam, but would you go out of your way to have a large party in your house during muharram? probably not. so would respecting that month’s significance for a shia be “sinning” just as wishing a christian “merry christmas”?