Because the prosecution is incentivized to cast the defendant in the worst possible light. When you listen to the prosecution and the defense talk about something, you could be excused if you thought they were talking about two completely different events. The defendant's position is based on evidence as well. Would you quote only the prosecution if it were Quid Pro Joe in the hotseat? I don't think so.Bias confirmation?
The prosecution's accusations are based on evidence. Why would I have to quote the defense? It's not like I'm an elected GOP official and it's Trump on trial.