Doom-nukem'ification

why do some people seem to turn their classic doom into quite literally duke nukem 3d with all the mods? this doesnt touch up to brutal doom but some dudes take their mods to a duke nukem level where there isnt much of original doom left but the title. even the monsters, textures, and everything else gets completely changed.

btw i am aware that some modders turned doom into a whole new experience/game but i hope yall know what i mean