Reddit is not a porn site but even with the nsfw filter that does not block many nsfw profile pictures, and people can make posts about nsfw things and have it not blocked by the filter
Also in the news there are sometimes people on stage who are dressed very nsfw-ish
And twitter is pretty taken over by nsfw and nsfw bots, I gave up on using it normally, what I did is I used the list feature to make a custom feed of three people I want to see tweets from, JayDLegend, Arlo, a nintendo youtuber, and MBG, a playstation youtuber, and I use it like that perfectly free of anything like those things
Youtube also especially can have this problem, what I do is I use it within the mobile firefox browser, which is very nice for two reasons:
1. The videos work within the background, so I can let the video play while I use something else or have my phone closed
2. You can get an extension named Blocktube that you can use to block either specific videos from appearing in your feed or entire channels, so with it you can easily get rid of the channels that push nsfw things, political slop, gaming slop, self improvement masculinity slop, anti woke slop, anything
After you block the videos or channel you can not even find them if you search for them on youtube, and if you try to go to the links for them, it is broken, you have to manually go into the Blocktube extension settings and delete the id of the video or channel from the block list to be able to find them again
