That may be true; in theory and in general for some specific sub-populations, at some particular range of dates in the past.

It is however, not specifically the typical experience nor true for all individuals across the history of the nation, especially for significant portions of the population across a great deal of the nation's history, and it is remarkably less true for many in the nation at present.

The tools of oppression are globally available, and are in use to deprive people of those explicitly enumerated freedoms both within and outside of the US borders everyday.

That's just the way it is, and the way it has always been.

For specific cases past and present, see: Native American treatment and conditions at any point in time from the time of the Declaration of Independence and the Bill of Rights until this moment in time.

Also see the ongoing cases of extrajudicial incarceration and deaths at the hands of law enforcement officers of uncharged and non-hostile citizens and residents without legal repercussions from either state or federal judiciary.

So, no, one cannot count on fair trial nor the presumption of innocence in the US, even though that is very much the promised state of affairs. Wishing does not make it true.

Fair trial is a thing in China (maybe not in political circles, like almost every country in the world), it's not at all like people think, if you are an average citizen that have a conflict in business or your landlord doesn't want to give back your deposit or you've done something illegal then clearly it's mostly fair justice, even firing staff is complicated in China, labor laws are pretty strong in general.