I think the big take away is that being right via a lecture doesn't do anything.
If you are morally right, and your aim is social justice, you should stop lecturing people, because it doesn't actually achieve what you are aiming for or really even advance the cause (in fact it may run backwards).
Instead, go out and do something. For example, defer typing up that long comment about how [x] is right and [y] is wrong, volunteer for some community service. Build shelters for people who need it. Offer pro bono services to marginalized groups.
If nothing else, simply live your way of life and out compete the people who were wrong.
But that 1000th internet comment you posted, even if it was "right", it didn't make a single lick of difference. So ask yourself why you really put it up.
Actually it's through Internet conversations and mostly online education that my mind was changed, my whole worldview in fact.
Quietly doing good is admirable. So is speaking up where people are talking. Both is even better still.
The very idea that your opinion would change over time terrifies people like PG. If you are useful, you must stay predictable. If you are not useful, you are a convenient target.
Stoking the classic 'us vs them' is the oldest trick in the book. Pay no attention to the man on the podium.