The #KillAllMen, #KillAllWhiteMen hashtags on Twitter are good examples of some of their activities.
Their backwards activism is often self-branded as "feminism", giving birth to things like #WomenAgainstFeminism. The definition of feminism has become sufficiently corrupted thanks to these people that women themselves are fighting against it.
I have a feeling it's their backwards "feminism" your parent commenter was referring to.
There are idiots on the internet. They have opinions. It's alright.
Like any other -ism people are always debating what TRUE -ismists believe. eg. Is Rand Paul a libertarian? eg. Is Obama a liberal? In general most people have opinions that don't fit into neat little boxes.
The concept of feminism becoming discredited started happening way before the term "SJW" existed. Both from outside the movement (See: the straw feminist trope) and within the movement (from a small minority of crazies).
No, there isn't. "SJW" is an insult used by their opponents. (Some of them might choose to adopt it, but most as far as I know do not.)
> The definition of feminism has become sufficiently corrupted thanks to these people that women themselves are fighting against it.
I've seen that claim, but I'm extremely skeptical that it's a significant phenomenon.
2nd wave is the one which frightened insecure men, and had some strong anti porn and anti sex messages from a few proponents. 3rd wave, in short, is why don't we all get along, sex is awesome, and if we help men with some of their problems with toxic masculinity, then everyone is better off.
edit: Here's a good & brief overview of feminism's waves - http://www.pacificu.edu/about-us/news-events/three-waves-fem...
And this is why nobody takes you seriously.