It makes the referendum illegitimate and its results questionable.
> Are you kidding me?
No, I'm not. For what it's worth, I'm not opposed to the idea of referendum at all, as long as it is done legally. I'm sure that if Moscow was so bent on having Crimea, they could have come to a political agreement with Kiev, and it would be legal and Crimea wouldn't have all those problems it's having now (e.g. lack of water, power, food price surges, crippled transport connections with the mainland, etc.). And Russia would have spent a lot less compared to what it's spending now on the war, maintaining a semblance of normal life in Crimea, and the sanctions.
The problem is that was not the goal of the folks in Moscow. They wanted to create a political crisis so they seized Crimea by force. When it didn't work, they inserted Girkin in Donbass. If Ukraine had given up Donbass just like it did Crimea, the next insertion would probably be Kharkov. And so on. It's not Crimea or Donbass the Kremlin is after, it's all of Ukraine - it's practically written on the wall. The nazi scares and the rest of the Russian propaganda are just an effort to garner sympathy from abroad for the military invasion.