Conversation almost never describes these implicit assumptions. As a result, each side ends up thinking that the other side is stupid, obtuse, biased, etc.
Getting to the underlying biases is hard.
As evidence, see any number of newspaper headlines, including this one:
http://www.independent.co.uk/news/world/middle-east/donald-t...
Ignoring the Trump bit, the headline says "kills 30 civilians, including 10 women and children"
Now, try to prove that the male / female victims were treated equally. And, that there is no implicit bias in male / female relationships.
I'm not saying that such bias is good, bad, or ugly. I'm saying it exists. And it underlies a lot of conversations, without anyone realizing it.
Which goes a long way to explaining why things end up as you pointed out.