Must've been some pretty good lulz then if they managed to get an entire region of people to start speaking that made-up language and pass it down to their kids, huh?

It was whole Soviet program of "ukrainization" with forceful study of "Ukrainian language" in schools as main one. But even today when you could be punished for speaking Russian in public, most Ukraine citizens speak Russian inside families and friends. Just watch any ukrainian videos on social. Every time, in case of real danger or fear, or anger or any strong emotion, all that "Ukrainians" always fall to plain Russian.

You also will not find a single "Ukrainian" who spoke modern official textbook "Ukrainian language" fluently. Because it never was native to anybody.