I just copy and paste URLs, I don't really use share buttons.

I do want to help spread our gospel, but I think that most people in those platforms are just to far gone to even care.

noone wants to learn about how to use X Y Z technology until you explain to them WHY they should listen. First start with the why, then tell them what their options are (what) and then tell them how to get there. First the why, then the what, then the how. https://blog.nowhere.moe/opsec/tutorial/index.html

Should I add features to share to those places?

personally, as i specialize in opsec on my blog (at https://blog.nowhere.moe) i go on forums and communities where people try to learn privacy / anonymity / deniability so i can just give them a link to one of my tutorials to help them learn about something more quickly

Those share buttons are trackers themselves. So it's not about "supporting" those websites by publishing content to them, it's about undermining the privacy of your readers and doing the opposite of what you preach, and "supporting" those websites by feeding them much more valuable user data. As another comment said, just put a button to copy the permalink and let them paste themselves if they want to share.

As for you sharing a link on the mainstream social media platforms yourself, I'd actually encourage that. Cory Doctorow auto-publishes links (not content) to his articles on as many social media platforms as he can (sorry, can't find the article in which he describes it). The point is that he still retains control over his content by hosting it himself, he controls the (lack of) trackers and ads, and gaining traffic from these platforms is still to his and his potential readers benefit. Bending your rules a little to reach more people and maybe even convert them to be more privacy-aware is fine.

I am self hosting it right now, but mainly for friends, family and acquaintances

In addition to rants, if you post tips, how-tos, explanations, best practices, suggestions, etc., I'd like to read your blog. Can you share the URL?

Can't they just copy and paste the articles URL from the browsers adress bar? Or are you blocking anyone with a referee from Facebook, etc.?

Wait, how can you even stop somebody from sharing it to facebook? It has a text box and computers can copy and paste a URL.

Your friends who use spying social media platforms can share them there, if it's a public blog. And if none of your target audience (friends and family) use Facebook, WhatsApp, Twitter, etc then there's no need for them to be shared on those platforms?

Also, ime from when I had to use Facebook because of a group I was in, the group was very resistant to any privacy advice. I think the vast majority of people on these platforms are on those platforms specifically because they don't care.

I do want to help spread our gospel, but I think that most people in those platforms are just to far gone to even care.

Backdoor them with the ideas.

Oh, no, nothing that elaborate. That's why I came to ask you guys. I can easily set up a "share to social" button that would give the reader the choice to basically post the link to 1 or many social networks. I guess you're right, they could totally copy the link, and that would force them to not be so lazy, lol.