to disprove something one counter-example is enough
This has got nothing to do with "citing selectively".
You've postulated something, then inviting me to check some sources that were supposed to prove your point; I have -- and lo and behold, there are definitions there that disprove your postulates. It is enough to bring up just one of them to disprove your point; "selective quoting" got nothing to do with nothing here.
Selective quoting is bad not because not everything is quoted (quoting by definition is selective in that sense), but because the selection is made dishonestly: that which fits is picked up, and that which doesn't fit, left out. Our case is different: you've proposed something in a positive statement -- a single counter-example is sufficient to overthrow it.
Had you said "there's no unequivocal consensus", that'd be different, and the pages you've pointed me to would prove your point; both pro- and contra- arguments would matter. But you've asserted unequivocally:
"(...) You think "documentaries" are supposed to be "objective," right? A common misperception...and that happens to be incorrect as long as there is at least one example contradicting this. That there may also be supporting examples, is irrelevant: to falsify a proposition one example is enough.
Documentaries are not "reporting," nor do they have any inherent responsibility to "educate." (...)"
Some people think documentaries do educate and must be objective, some don't. So at least you can't say that those who believe that documentaries are not free to be purposely misleading are wrong. This is so according to your own sources.
Also, you say yourself "a common misperception". The very fact that it's common, combined with what your sources say, shows that this is not a misperception. A common view, a common opinion -- OK. There's nothing wrong with holding such an opinion though.
Now, if none of your sources stipulated that, you'd be fine (as far as your sources go.) But there are some, so it is no misperception to expect a documentary to be objective -- and practically, I think, that's precisely what most people do.