Safe mode is meant as a means of diagnosing a problem with your computer or more specifically the configuration of your computer's Operating System. The smallest misconfiguration can cause catastrophy- so why is it good to start the display at a higher resolution and with a larger color palette?

If I have a problem to fix with my display drivers (or modules), I do not want my "safe mode" to also be affected by these problems. Maybe that's just me, though.