I realize you can just answer, “mysterious aliens beyond our understanding,” but why would a space probe have a mandate of either talk to a whale for 30 seconds or destroy Earth and disable everything in its path on the way to Earth?
Why? What does that achieve?
“Plot device.”
I know this movie is a subculture favorite (my personal theory is because of the popularity of who directed it), but except for some funny moments it’s one of my least favorite; not least for how much it has to lean on inexplicable plot devices. At least in ST:TMP, Vger had a motivation for blowing things up and being petulant: it clearly had its own understandable desires.
I have warmed up to it over the years, but I admit I have always thought of it more as “Comedy Star Trek” than “Star Trek with Comedy.” But now we have Lower Decks, so…