Its a societal thing.

Embezzling is universally bad, and can be proven with "objects" ie transaction and contracts and the like.

the pernicious problem with sexual assault is that first you need to prove the assault happened, which is hard, because its often in private with no witnesses.

Second you have to prove consent.

worse consent can be withdrawn, especially if things go too far or violent. so it might appear to witnesses that it look ok when they saw them.

Finally the elephant in the room. There is a taboo around non straight male sexuality which varies by region. Its very easy to paint the cliamant as someone with loose sexual morals, filled with guilt/loathing lashing out to smear an innocent party.

The problem for the victims is that agreeing to sex is vaguely taboo for non-straight men to do. Therefore they are at fault.