I’ll gladly clarify my points ;) But first, a little background:

I came to Medium in April 2017. There was no payed membership and no MPP (I guess, first invitations to join both the “green halo club” and MPP, were sent around that time, to test it). This is the first major difference to how things look today. The second major difference is that back then you had only one kind of timeline — homepage, “from your network”, tags, search, etc. — all were identical in that they all listed, in chronological order (from latest to oldest), all articles and all responses (i.e. if you followed someone, you saw also their responses in “from your network”, etc.) . As you can imagine, this resulted in a truly incredible community network and outreach that one could only dream of on any another platform (service or self-hosted). Simply a blogger’s wet dream come true.

Then, I guess at the end of summer of the same year, MPP and payed membership went on-line, and the whole platform started to shift toward what you can see today. I tried to resist the trend, but more and more people from my network started to join MPP and locked their articles, so at the beginning of November 2017, I bit the bullet and payed $50, only to be able to interact further with people I missed, who were now behind the paywall.

Also the technical side started to look very differently — no responses in the timeline, homepage stopped listing people I follow and instead it pushed editorial and algorithmic picks, etc. (I recommend you go and type “Medium changes” in the Medium’s search bar). And this technical side, which slowly but steadily dismantled the community, is why the majority of writers went away. The outreach dwindled to almost nothing (especially for newcomers), and staying in touch, exchanging ideas, became much much harder.

I became so demotivated, I cut the losses, and at the end of January 2018, I canceled my membership. As for MPP, even though I didn’t like that idea, I was not so proud as not to try it, but — and it’s a huge but — as you may know, it only works with Stripe, which is not available where I live, and creating an US based ltd with US associated bank account (for ca $500 but that is not the main problem) to circumvent it is a nonstarter for me. There were many complaints about Stripe-only policy — to this day Medium is deaf to them.

So, now for the castes.

There were always two major groups on Medium — authors (many of whom are also avid readers) and readers-only (note, I don’t consider these groups as castes). But with aforementioned changes, especially payed membership and MPP (the technical side was just a way to drive users toward them), an economic (access) stratification took place. E.g. in the beginning there were writers who joined MPP simply to be able to afford the “green halo” and stay in touch (but yes, they were a minority — but again, search for “Medium changes”).

However, if you are not in MPP, your articles are not eligible for curation, hence never appear anywhere except in “from your network” of people who follow you. I used to use tags to circumvent it, but Medium changed that too — now there are only top stories (or former editor picks) and their archive. On top of it, Medium, as it is today, started to attract people who explicitly go for money and are not interested in community or exchange of ideas. Go figure.

As for conservatives — first, I would not consider them a caste (as I would not consider a caste any other such opinion group). Caste, in my book, is a group of people who have exclusive privileges. And second, there were plenty of conservatives on Medium, as well as libertarians, alt-left and right, fringe, hard-core mainstream, or what have you. Anything. All in all, if there was a opinion in the world, you could find its voices on Medium(and the vast majority was pretty articulate and intelligent). When I came here, Medium was truly a place where words matter (a lot of those people are still here, they are just inaccessible, because if you don’t know what to search for how could you search for it, and all parts of Medium are heavily curated today).

And this brings me to another point — I didn’t join Medium only to present my ideas, but I choose it mainly because of community. It was (and in a way still is) one of the places where one can have the most intelligent discourse on the Internet.

I hope that I clarified the points you asked about.