It’s some sort of power play, parents are authority figures and it’s a very popularized term, so maybe saying daddy instead of boss or Mr officer feels easier, as an introduction to sub/dom play.
The people that actually have daddy issues are different though.
Even if all the far-left parties only get 1% or 2%, if the moderate left arty doesn’t have a clean majority, they need the votes of those far left parties to form a government, and thus the far left parties can negotiate some stuff. It’s not useless to vote third party.