All else being equal, productivity might drop. But by hiring some less productive people as well, there are likely some non-productivity-related benefits to be

All else being equal, productivity might drop. But by hiring some less productive people as well, there are likely some non-productivity-related benefits to be enjoyed, such as broader brainstorming about how to make the product/service work well for a more diverse set of customers, and whatever value might be created by the morale boost (people generally like to do good) along the way.