Censorship is inevitable. But here, the censorship is decentralised. In other words, when I upvote your post, I am choosing to make your post more visible than other posts. Everybody is technically censoring content by upvoting and flagging. And the whales have the greatest power in this censorship.

As for your feed where you follow people, nothing is censored. Even if you follow a user who loses their reputation, their posts still come up in your feed (just greyed out).

Don't worry I understand there is a lot to catch up on. I felt lost when I joined too and there was not as much for me to learn back then, things here change pretty fast.

At the moment it is a large handful of whales who control what comes to the top of the trending page and what gets hidden from view (but not in your feed). However the idea of this decentralised economic system is that with time the power will be distributed among those of us who are most active and most rewarded by the whales. The whales are powering down to reduce steem power and selling on the market, while the budget of rewards stays the same, so many minnows are growing into dolphins and the odd dolphin might even become an orca whale. But it takes time and I have no guess as to how much time. I could speculate but I don't want somebody smarter than me to see this and call me out on it lol. Here's a post by dan that might make things clearer. I advise you to read the content of @dantheman, @ned and @steemitblog first, as they are the creators of the platform (dan & ned).

Don't be afraid to ask questions to anybody you see with a high reputation (they are more likely to give you more accurate answers). Don't bother asking anybody with a rep below 50...

EDIT: I believe there was some additional "censorship" added. The NSFW content can only be found under the NSFW tag. None of the other tags show NSFW content. But that just means to see that content you have to go to https://steemit.com/created/nsfw

So even pornography is allowed.