Dear CC,
You often bring up interesting points. If you'll excuse me, I think that you're slightly over-reacting this time. Some times of the year like Vaisakhi/Baisakhi/Vesak/Visakha/Buddha Purnima etc. etc. are celebrated in many cultures and parts of the worls, and in many different ways. Not knowing the details of what made you react, I think that I was more puzzled the first time I heard of a Good Friday ball in Lutheran Sweden.
If faiths and/or their revered persons or deities are not explicitely ridiculed or demeaned, I see nothing wrong in celebrating Spring in any way the celebrators might seem fit. The fact that some persons might see other connections and/or reasons for celebrating the start of the cultivation period shouldn't prohibit the rest of the world from making their own decisions. For example, I don't recall ever having heard of a Christian in Sweden protesting against the ubiquitous Midsummer dances around the maypole, which undoubtedly is a very "heathen" practice.