I saw this on my dashboard a while back, and I actually got excited- completely ignoring the name.
If this ever gets made, and with all the features planned, I feel like it would be pretty useful. That's a big if, but for argument's sake, let's pretend it happens.
While almost all the features can be used for SJW purposes, they could also prevent the average user from being unnecessarily harassed by said community.
For example, editing posts and having all reblogs show the edit does allow clarification. There are plenty of situations where one user slanders another user (calls them a pedophile/white person/cis/etc), and the post gets reblogged by thousands of people. However, a few days later, the same person apologizes for their original post and attempts to clear the other user's name. The way tumblr works, however, means that people will most likely see the first post on their dashboard, never get the second post, and continue believing some lie. To avoid blatant backtracking, it might be nice for edited posts to be either an addendum only, or have a link to previous versions. That isn't what's proposed currently, but IMO, it's still better than tumblr's current system.
Deleting posts with reblogs sounds silly, but I'm assuming it's for the same purpose of getting people off your ass because you drew Rose Quartz one shade too light. I think that editing your posts is enough.
Blacklisting tags is something I sorely wish tumblr had, and it is because of the format. Stuff is delivered to your dashboard from people you watch, regardless of common interests. I could have a friend who loves Undertale, and I could just be sick of seeing Undertale- but still want to see the rest of the stuff they reblog. It isn't necessarily that people are triggered. It's that not having blacklisted tags detracts from the purpose of a dashboard, which is a frontpage of things you enjoy looking at. I've had friends who download xkit simply so that they can get rid of as much SJW bullshit posts as they can from their favorite artists.
I would assume that whitelisting tags, ie, making all posts under them appear on your dash, helps the same way; its main purpose is just to help you find material you enjoy.
And of course, communities sound useful. Abusable, but useful.
Even though all these features can be abused by SJW's, I'm not sure if they're entirely catered towards them. Briar Nexus/Haven/whatever it was called had a much heavier emphasis on being a complete SJW hugbox. Pillowfort, to me, seems a bit more focused on keeping various user groups separate (SJW's, average users, anti-SJW's, that weird daddy dom community) so that they don't bother each other and boil into drama.