Like Alan said, usually when discussing edits, we refer to "destructive vs. non-destructive", where as when discussing file formats, we refer to "lossy vs. lossless".

If we take white balance, for example. Is adjusting white balance truly "destructive" when performed on a raw file? A raw file can not be viewed in its native state, as its just a bunch of "raw" sensor information and camera data. The information from a bayer array is not viewable directly...it has to be processed to create RGB pixels that may then be viewed as an image.

If I render a RAW file with all default settings, am I "destroying" information? Or am I simply interpreting it? When I change the white-balance setting, am I "destroying" information, or simply changing how I interpret the information that exists?

Lets contrast that with JPEG. A JPEG image starts out "lossy", since the original data has already been interpreted. Any adjustments from this point on are not from "original" data, they are from a previous interpretation. Technically speaking, within considerable limits, you could make non-destructive edits...but only within considerable limits. The data has already been partially destroyed, so you have to wonder, how much more destruction am I causing by adjusting poor data?

When I work with a RAW image in Lightroom, and adjust exposure, white balance, tone curves, etc., all of those edits are applied to original data. Every additional adjustment is refactored into the RAW processing, and applied to original data. If I adjust white balance several times, I'm not losing any data...the "total" WB adjustment is applied to the original data when it is rendered on the screen. Its not as if one WB adjustment is applied, then another on top of that, and another on top of that, which indeed would be destructive. If you apply a tremendous amount of edits to an image in Lightroom, you'll start to notice lag as you zoom or pan the image, make additional adjustments, etc. This is because any adjustments are reapplied to the original RAW data when it is rendered on the screen.

Assuming you do "clip" reds in a particular WB edit. The information is not actually clipped, since that is just part of the overall processing applied to the raw bayer sensor pixel data when it is rendered to the screen. If you make another WB edit later on to "recover" those clipped reds...they can be recovered in their entirity, without any loss, since its just a step in a processing "pipeline" that is executed any time the RAW image is updated on the screen (i.e. zooming in, panning, making other edits, etc.) The only time information is actually lost when editing in RAW is when you save to a normal image format. It doesn't necessarily have to be JPEG, you will still incur a loss when saving to DNG or TIFF.