I think you both make excellent points, but there's another facet to Tumblr Social Justice Warriors. It's something that will undoubtedly be discussed when we record an episode on it*.
Part of TSJW culture is that you get to feel superior. It's not that you're trying to honestly make the world a better place. It's not trying to get people to stop using "gay" to mean "bad." It's not about encouraging people to write about nonwhite characters. It's not about telling women that their sex drives aren't evil demons that bestow the Curse of the Vile Slut on them for 9,999 damage.
It's about getting mad at an artist if the character they drew happens to be white. It's the joy of being the first to blow the whistle when someone says "no duh" in response to a statement of the obvious. It's about spontaneously deciding that telling people to bathe is ABLEIST and getting the chance to call in the cavalry when someone dares to say "no seriously, take a shower, people." It's about dinging someone a few points when they don't post a header saying "WARNING: THIS POST MENTIONS THE WORD 'MURDER'" It's being a part of the crowd when they decide to run someone out on a rail for quoting a movie that has a slur in the dialogue. It's wringing your hands about "appropriation" when someone who isn't black says "what's up?" It's getting worked up because one picture of a brown-skinned cartoon character is slightly lighter/darker than another picture of the same character, even if it's just a matter of different lighting in a given scene. It's about saying "butthurt" is a homophobic term. It's about being outraged that someone would call a specific statement, story, song, or artwork "progressive" because it didn't have ENOUGH underrepresented groups.
Tumblr Social Justice is a game. The rules are: (1) whoever doesn't do anything even remotely objectionable comes out on top, and (2) whoever says anything about people needing to do something, or jokingly mentions death, or draws a brown person with a slightly different shade, or ANYTHING ELSE REALLY loses points and social standing. Then you get to be the high and mighty savior because you called them on it. You didn't make a joke about cutting a dude's head off with a chainsaw, BUT THAT GUY OVER THERE DID! HE SAID THAT! HE'S THE PREY NOW! 8DDD Then you get to tell yourself what a mighty, progressive warrior you are, and you get asspats and e-kisses from your peers. I mean what are they going to do, defend the transgressor? Of course not! Then they'll get dogpiled too!
The way Tumblr has twisted social justice is goddamned sickening. Social justice is a real thing that needs to be addressed by mature adults, and these kids have turned it into ridiculous little RPG where you scramble to keep all hit points you can. When you cry wolf that many times, you annoy people into ignoring important issues. When a friend yells at you because you greeted a friend with the term "dude," you file that away in your brain. The next time you might actually say something truly offensive, like purposefully misgendering a trans person as a joke, and if that same friend freaks out, you might just think "well yeah, but you freak out about EVERYTHING so this probably isn't a big deal either." THAT IS AN ACTUAL, DAMAGING PROBLEM CAUSED BY THESE TUMBLR KIDS, AND THEY'RE DOING IT FOR NO REASON OTHER THAN TO MAKE THEMSELVES FEEL GOOD WITHOUT DOING ANYTHING MEANINGFUL.
So yes, I can see why they wanted to pounce on me for saying "cunt." Now they're perfect angels and I'm some gigantic turd. Oh but please, don't bother actually saying anything to me, kiddies. Just whine about it and bask in all that praise for your wonderful sensitivity.
* I have around 50+ links for such an episode, and it will probably happen once the headache of previous Tumblr-themed episodes wears off.