Your response which consisted of calling out my question as a "gotcha question" tells a different tale. You very clearly distinguish certain opinions from others - as would anybody.
It is my opinion that if the facts are presented in a straight forward manner the student should be intelligent enough to come to their own conclusion.
What facts do you want to see presented, though? You can't cover everything in class, so you have to prioritize.
So what facts are to be prioritized?
The millions of deaths and enslaved caused by the Transatlantic slave trade, or the cutesy legends surrounding George Washington, who could not tell a lie and once chopped down a cherry tree?
The genocidal massacres of the Native population, or the lives of "great" Presidents?
The misery of the working class during the Gilded Age, or the charity works of the robber barons who profited from them?
These are rhetoric questions, of course - but I hope you can see that it's not so simple as to have facts "presented in a straight forward manner".
We cannot tell everything, but what we tell and what we leave obscured can be just as manipulative as any straightforward attempt at forcing an opinion down somebody's throat - and potentially more insidious, since the person who is being taught will not realize which facts have been omitted for a long time.
Your two examples are basically "gotchas".
Only if we adhere to ridiculous blanket statements like "don't teach opinions", which is evidently self-contradictory and breaks down at the slightest contact with reality.