Laws could be, need to be, better, but I think the thing that's always missed in these discussions is that the process of getting justice can itself be a burden.
It's not like I'm very familiar with these exact processes myself, I should be clear. But just think about it on a slightly deeper level- you can't just make a police report and walk away and they handle it all for you, right? You're now tied to it, you have to keep participating in it. Even if you're somehow treated incredibly respectfully, that still takes time and money and energy.
And meanwhile, you're known as the person who made that accusation. And that can obviously ruin friendships, get you treated badly, can hurt your ability to get work, ruin your ability to be in communities where the person you're accusing is respected, etc. And what if, in the end, they get away with it? Or if you just can't deal with the process anymore, and you have to drop it, and without you there's nothing to prove it? Now you're known as the person who made a false accusation. And course, even if you're lucky enough to get a guilty verdict, some people are going to blame you for it anyway or view you as trouble.
And it doesn't even matter if these concerns are realistic or not in practice, because fear of any of it being the case is part of why people will stay silent. So... it's not just a matter of the law, really. And honestly, even if society was far better about these things, it'd still take that time and money and energy to deal with, and that's a thing people have to judge if they're up for.