Is the Dutch ruling royal family, the House of Orange, named for the fruit or the color?

It is neither. It is named for the Principality of Orange, located in the southeast of France, and initially the name had nothing to do with the fruit or color. Later, however, it did become associated with the fruit.

The best explanation can be found at https://en.wikipedia.org/wiki/Orange_%28word%29, second paragraph in "etymology". According to this source, the naming influence was Arausio, a Celtic water god.