My two cents on the Purim debate:

If you hold the position that we don't HAVE TO celebrate Purim, I can understand that since it was a decree from human ruler and not from Moses with Yah's authority. But if you have the position that it is WRONG to celebrate Purim then you have to argue that a whole book of the Scriptures is not relevant. Which I have heard people do. The last person I knew that held that the book of Esther was not relevant eventually disregarded the book of Hebrews and then Yeshua Himself. So avoid the I don't like this book of the Bible band wagon.

So in short: Purim is optional, not a moral issue.