I frequently hear complains from people about individual Wikipedia pages but most of the people who complain only complain outside of Wikipedia. Wikipedia is inherently democratic. If you read a Wikipedia article and think it's very problematic, take five minutes and write about why it's problematic on the talk page of the article.
Wikipedia is an important part of the commons. If you think from an EA perspective those five minutes (or even more if it takes you time to search for sources) have a good chance of being time spent with a good EA return.
While recruiting people outside of Wikipedia to individual pages to engage in discussion goes against Wikipedia's rules, simply engaging on Wikipedia and voicing your opinion is helpful. It makes it more likely that consensus on the article shifts in the right direction.
This is not true. I could drone on about the Official Policy but maybe the better rule-of-thumb is:
(1) Don't edit articles to push one side of an existing hot-button political issue, it's hopeless unless you have a ton of wikipedia experience and a ton of free time,
(2) If you write things that are correct and widely-accepted, they're pretty unlikely to be deleted, regardless of what source you cite, or even if you cite no source at all. If other people don't like the sourcing but do like the text you wrote, they're more likely to improve the sourcing than to delete the text.
(3) ChristianKI's advice was actually posting on the talk page rather than editing the article directly, which is always a good bet. And if the article is so neglected that nobody does anything about your talk-page comment, then that's a good sign that you can probably just go and edit the article without anyone bothering you.
I'm not sure what you were expecting. There are a gazillion people who think "circumcision" is the obviously correct term, and a gazillion other people who think "genital mutilation" is the obviously correct term. Of course there's going to be an Official Policy on this, settled long long ago, otherwise people would spend all day in endless "edit wars" where one person changes it, and the other changes it back, and the first one changes it back again, around and around forever. You're welcome to think that the Official Policy is wrong, but I don't think it's reasonable to expect that you can just easily "fix this problem" the way you can easily fix other problems on wikipedia pages.
I don't think that's fair, I think there are lots of articles that present both sides of a controversy pretty well, for example minimum wage seems pretty good.
I don't want to say this never happens. I think you need a sufficiently "thick skin" that if 10% of your edits are deleted for stupid reasons, you're generally happy about the other 90%, not stewing over the 10%.