You forget that the corporation usually pays for staffing costs of the workers who created this work, plus overhead, plus promotional expenses, and possibly even entered into contracts on the basis of the work.

A corporation spends more money to create a creative work, so its actual damages are significantly more -- why should it be forced to swallow those other costs? (Even staffing costs are damages b/c those costs could have gone into some other endeavor).

Furthermore, work created for profit receives greater protection precisely b/c of the money interest involved -- if the work was created for free, the presumption is that the creator didn't carry about money, and so is not harmed much by infringement.