NASA often alters the coloration of pictures but the reasons are not necessarily sinister. In the case of gas giant planets or Venus a true color photo would often show very little or no detail. The swirly cloud patterns of Jupiter would barely show. So sometimes it is better for study purposes to use false color. In the case of stars, galaxies and so on they are often observing in wavelengths where you would see nothing at all. Often researchers do not have the same common sense desire to see a true image that you or I do, if they have an instrumental readout of spectra they are perfectly happy just having the dull data. Just look how long it took them to point a camera anywhere other than at the landing pad of the probe. NASA is also to a certain degree a marketing machine, how could they sell the allure of going to the "red" planet if it doesn't look red?
