You are not alone on the planet. Hundreds of pods have crashed on the planet and people are waiting to be saved.
And you will need to keep them warm, fed and under a roof. Or they will get unhappy.
Deconstructed a machine that had no colonist employed and icon stays forever, when using construction robots.
Tried different vanilla/modded furnaces/assemblers. https://i.gyazo.com/190497a8b5c9d86f6b20e7dae4cf912d.png
If i mine it manually, the icon disappears correctly.
Also not only icon stays, but vacancies amount doesn't decrease. So a player ends up with colonists being busy on buildings that don't exist anymore, if they were employed on buildings you remove with robots.
