You are misrepresenting the status quo when you're insinuating that some "establishment" conspiracy will be suppressing the usefulness of violating fundamental rights, such as assumption of innocence, in their quest to defend "political correctness".
This is obviously wrong. Such rights, and others like privacy or the right to a fair trial, only make sense under the assumption that their violation would in some ways benefit law enforcement. Otherwise there'd be no need to protect them.
While the argument that, for example, "torture doesn't work" is sometimes made, it is always secondary to "our civilisation is better than that, and it is strong enough to accept a (small) hit in effectiveness in the defence of fundamental rights".
So when you believe you've stumbled onto some greater truth, and that the world needs to hear some tough talk of realism, you've simply missed the essential message of enlightenment, and are reverting to 16th-century morals.