I don't think the OP is asking whether wearing a kilt would offend Catholics, only the particular tartan.

MacSpadger, the article you linked to from 2005 is not about the Dutch MacKay tartan, which has been around since 1965. The idea for a Dutch tartan came from a men's neck tie manufacturer because of the popularity of tartan ties in the Netherlands. The Scottish Tartans Society was consulted and it was decided to base the tartan on the MacKay, because of the great connections between that clan and the Netherlands. The tartan was created by a simple color change. The orange in the tartan is evocative of William of Orange, who was notably Protestant. But the color was chosen no doubt because of the historical significance to the Dutch people, not out of any anti-Catholic motivation.

As a Catholic myself, I certainly would not be offended if you wear it. I realize that the color orange has certain politico-religious connotations in Ireland, but my feeling is that someone who chooses to take offense simply because the tartan you are wearing contains that color, would probably also be offended by citrus fruit and traffic cones. If someone should get offended and ask if you are an Orangeman, etc., just explain that the tartan is the Dutch tartan and you are wearing it because your family is part Dutch. That should be enough of an explanation for anyone.