Maybe it's as simple as I don't understand the legal system in the UK, but I think people are inaccurately conflating the previous situation with Bissouma, and also charged vs convicted with a crime.
Please correct me as necessary on the differences between UK and US law, but this individual was arrested, which means that they believed sufficient evidence existed to bring charges. He was released on bail, which explicitly means that he was charged with a crime or multiple crimes, and both hearings and court dates have now been set regarding those charges. If charges aren't made then people aren't released on bail, they're just released.
Contrast with Bisssouma. He was brought in for questioning, but not charged. Strictly speaking, questioning is voluntary up until the point where someone is formally placed under arrest and charged with a crime, and then they are cited, processed, and assigned a court date to review those charges and whether sufficient cause exists to try those charges in a court of law.
This fucker was arrested and charged with multiple counts of rape. The legal system is now in motion which will adjudicate on whether he's guilty of the crime(s), but he has been charged.