I think that an accusation of rape does stick and ends possibilities for relationships and careers more than being charged with other possible crimes.
It isn't Liam Allen's fault how he looks and talks - I don't think it's reasonable to bring that into it, any more than we'd make comments about a woman who had been accused of sexual assault. He isn't the only young man to be the subject of a story like this.
The police would not necessarily think they had proved his guilt beyond all reasonable doubt in order to go to court. They may have felt there was enough there to make a compelling case for it, which is different. Ultimately, it can be as hard to prove a man's innocence as his guilt in a matter like this and the 'evidence' may simply be testimony, making a decision to take it to court very speculative.
In Liam's case, it was certainly be about one woman's credibility and whether she told the truth. She told police it was rape. She told friends it wasn't against her will. She's lying to someone. And no one with the ability to hello Liam knew about it, because the police wouldn't disclose it or simply didn't know, despite the evidence being right there in their possession. One doesn't need to be a rape apologist to feel the time is right for reflection.
This mishandling of evidence could be a sign that police are helping men get away with rape only if it was a coincidence that they withheld evidence that would have vindicated Liam on this occasion. There is no such evidence that it was a coincidence. More analysis is needed.
We already know that not enough rape cases are successfully prosecuted. We know there is a conflict between the justice system (innocent until proven guilty) and the way police are trained to approach rape ("we believe you when you say that this person has committed a crime and will do our best to prove it for you"). It's a subjective position to take that is at odds with the contradictory position held by the court. If we need to have a special 'guilty until proven innocent' approach for rape, let's debate the ethics of it and decide to do it properly, rather than shoe horning it into the police's role, which is currently meant to be objective.
I think it's perfectly reasonable, in light of these cases and the contradictory position forced upon the police, to critically evaluate the methods being used to drive up rape convictions. If it came to light that the mishandling of evidence is even handed and helped in securing rape convictions, I and every other right thinking person would be delighted. But it is possible to have a problem securing rape convictions and also to have a problem ensuring that successful rape convictions are reached safely and fairly. It seems we may have both problems.