Alright since I'm the token tumblrite and tumblr native, here are my recommendations:
- Change the URL. People don't fucking know who Stirner is, and if they looked into him, he's edgy as fuck which is unappealing. Furthermore, the first time I came this board and saw you calling things spooks, I had no clue what you were talking about and thought it was some bizarre re re-purposing of the anti-black slur. Just say "social construct" when it's appropriate. They're not ready for "gender is a social construct" yet, though. It's pretty TERF-y and seeming like a TERF or being chummy with TERFs will get you shunned.
- Holla Forums loathes identity politics. Don't "sperg out" (ugh, I hate to use that since I have several close friends on the autism spectrum, but I can't think of a better way to word it) over it. It's entirely possible to successfully marry many of IDpol's complaints with leftism. That is, the source of the prison-industrial-complex, police brutality, eurocentric beauty standards (fucked up beauty standards in general, tbqh), Islamophobia, anti-immigration laws, the effects of imperialism/colonialism, etc. is capitalism. They see capitalism's horrid effects, but many haven't correctly identified the source. This isn't necessarily their fault. They wouldn't have known any better. You guys would call me a SJW when I was about 14-17 and I truly believed I was doing the right thing. It never crossed my mind to look into communism as a "social justice" kind of thing until relatively recently. Capitalism's funny like that. Porkies don't want you to think it's relevant, useful, or moral, so people don't consider it a possible solution to be looked in to. Most are welcoming of it when properly introduced. Also, please just be aware that most users are pretty young. 13-19 seems to be where most of them lie. For example, I'm 18 and feel like an ancient relic. They're just kids.
- Leave people under 18 alone. Tumblr's weird about considering 18 year olds adults because they still aren't adults, emotionally and mentally and all that, but it's the legal definition of adulthood so they think they're fair game. If you attack people under 18, especially people who are like 15 and under, you will become very unpopular very quickly.
- Don't speak of non-binary genders, neopronouns, or otherkin. There's no way to do it "right", so just don't even mention it. It's not even that important.
- The Alyuna/political girl waifu shit won't work. Keep it to the chans.
- Don't link to Holla Forums. Don't post shit with Holla Forums's signature on it or anything. Don't even bring it up. Don't speak of image boards. It's actually quite fine to say you visit halfchan and jokes about what you find there or funny screenshots or whatever are fine and can get thousands of notes, but you really don't want to bring them here in search of the source of your posts or a like-minded community. Holla Forums is off-putting to most people and it will turn them away from you if they link your blog and Holla Forums together.
You guys really don't have a grip on the general culture of tumblr. It's fine and understandable since you don't use the site, but it's not the same site as it was circa 2013, nor does its surface accurately represent the true userbase.
There are actually quite a few communist/leftist popular bloggers and there's an enclave of specifically communist users. Memeufacturing is the unofficial leader of 14 yr old tumblr as this point, which I'm not sure how it happened and I don't actually like memeufacturing or 14 yr old tumblr culture, but at least The Youths are included, too. There's also communistbakery, somuchforthetolerantleft, the-red-church, beyonslayed, gotitforcheap (IIRC), and a ton of others whose URLs I can't remember at the moment. All popular, well-known leftist bloggers, mostly for the older half of tumblr's audience (16+). Even I make regular communist posts (both serious posts and just fucking memes) and they're well-received, even though I don't tag them. Posting them has made my socdem friends more sympathetic and the majority I'd say have even converted. Sort of a peer pressure, follow-the-leader kind of thing, I guess. Basically, you aren't the first, but 4.5k followers is a very healthy audience I'm sure you can do at least something with if you pull this thing off. Whether it's actually a good idea is something else, entirely.