Hmmm. Your post contains a lot of things that you think women should be doing. Lots of "should do" this and that.
Not everyone will agree with you about the government (I'm not a Tory, but there are plenty of people on here who are, and that's fine). Plenty of people will already believe that the government is doing its best for future generations.
The difficulty with your post OP, is that it contains a lot of expectations that people will share your opinions and views. Not everyone will.
I don't see a lot of downright nasty posts, but I do see posts that are blunt. The problem is that with the written word it can be very difficult to discern tone. As others have said, this is typically more on AIBU - the specialist boards tend to be less blunt. AIBU/Chat are designed for sharing opinions really, whereas other boards are more naturally geared towards advice and support eg/SEN board, property, relationships etc.
I take your point that life is rarely as simple as the solutions that are sometimes offered, but as readers we all only get a glimpse into each others' lives. And sometimes it takes an outsider to offer up a radical solution, or to make you think seriously about an idea you'd previously dismissed.
And of course, there are sometimes those posts which are infuriating. Sometimes we just need to vent, and that's fine. But other cases where a poster expects some kind of magic solution where very clearly their expectations are unreasonable or unrealistic - it's hard to know what to say other than pointing out the obvious.
I think for sure there are posts which feel a bit harsher than others, but I think overall there are way more supportive, kind, helpful comments. And sometimes the most helpful comments are the ones that the poster doesn't really want to read - but probably needs to.
Also, the people that you're judging for not commenting kindly enough to those who are wealthier - you have no idea what they're going through. When Jenny is worried about how she's going to put food on the table for the rest of the week, it can be really hard to drum up empathy for Julie who's posting about whether she can afford to put her second child through private school. Sometimes, with the best will in the world, it's hard to be kind and supportive when you're struggling to survive. People aren't robots and emotions can influence what's said.
I don't think MN is any better or worse than other social media platforms. I like MN because it provides a really interesting cross-section of opinions - just look at this post, perfect example. Lots of varying comments and views and people disagreeing - that's what makes it such a fascinating place.