Well, despite your view that considering those accused as innocent is lenient, the burden of proof falling on the accuser is in fact a core tenet of common law

Well, despite your view that considering those accused as innocent is lenient, the burden of proof falling on the accuser is in fact a core tenet of common law justice (and supported by the 5th, 6th and 8th amendments to the Constitution). And if someone accused you of wrongdoing you would see the value in that. Humouring your dislike of such judicial proofs, it is reasonable to view the system of justice as a series of ever more precise and expensive diagnostic tests. At all stages there is a desire to finalise the proceeding to reduce the bill for enforcing the law, with the dual goals of (A) not letting too many innocents be shafted or (B) too many guilty walk. Many would argue that the current system is broken. I doubt the fix is just fair trials, because most of the defendants are indeed guilty. It is related to lack of opportunity, a predilection for jailing people for minor offences rather than rehabilitating them, and systemic racism.