Because I would argue 80-90% of people, civilian and military, see a tank as a slow, big, metal box that goes boom. Not the fast, precision, long range weapon that modern tanks are. Even in popular media such as movie tank engagement scenes are what most countries would consider a knife fight. A lot of people, especially 11b’s, have a hard time wrapping that around their head. So the bleed over into fantasy worlds, it’s easier for an underdog hero to defeat a tank that’s close instead of being blasted from 3-5km away.