Aside from your uncharitable interpretation: it is really not difficult or time-consuming to support this. It's just setting and checking a single boolean flag, in fact it may simply just be a few lines at startup if the tool already supports color options via cli args.
Indeed, if one uses the termcap or terminfo libraries (or the likes of unibilium) to obtain the control sequences for colour from those databases, instead of hardwiring them into the source code of print statements, one gets the TERM=dumb convention implemented entirely for free.
In this case it seems pretty easy to contribute a patch? Mature projects have unit and screendiff test suites that need to be updated and extended to verify the new case, so it might not be THAT easy even for a trivial change.
