While what you say is true, it is even worse than that.
It's not only that most people don't know that proving rape in court is exorbitantly difficult, ending in extremely few convictions that do not correspond to the number of true accusations. Many people, particularly men, will believe that in fact it is more likely that in a case like this the accuser is a money-grabbing opportunist, than to give her the benefit of doubt, even in the presence of overwhelming evidence. Misogyny is not rooted in disinformation, but like racism and other pathologies like that, on irrational bias.
Even though the number of sexual assaults against women is far larger than false accusations by opportunists, people will favor the hypothesis that matches their bigotry, even more so if they happen to have a liking for McGregor as a personality, which of course millions do.
This is a man with ludicrous amounts of money, proven criminal record, who has shown not only reckless but harmful behavior to civilians, with many accusations of this sort, a proven drunk and drug user, angry party animal, who also has power and very deep connections in the Irish criminal world. This woman is a hairdresser, a former drug user and drunk, who partied like an idiot as an adult woman in her late 20s. The quality of legal representation she can afford, the potential of corruption, and the danger this presents for her, does not yield an even playing field. Judicial systems are often very defective as instruments for justice, and this case provides sad but disarming evidence of this.
In this case, there is one simple and definitive fact: the woman was battered badly, the doctors that saw her testified to her condition, having a tampon removed with a forcep, visibly traumatized, crying and shaking, bruised and injured throughout her body.
Granting the benefit of doubt to McGregor because she has memory gaps to claim this was the result of "consensual" intercourse is so ridiculous that the doctor when cross-examined by McGregor's lawyer said that in hundreds of abuse cases under his watch he had never seen anything like this.
Anyone who defends McGregor at this point is a sack of shit, and that this is not a criminal case is a travesty. The guy should rot in jail, or worse.