Plebit is a dumpster fire filled with angry woman trying to take down the "white male patriarchy", Every type of Agender alive blaming Republicans and Christians of crimes against humanity, Woke Warriors/Antifa labeling every white male not part of their group racist and a NAZI, and just your general NPC looking for some kind of "belonging/tribe".
The only good thing about Plebit is that it is a honeypot that attracts most of these types and keeps them off of sites like HN. Although I have noticed that there is some bleed over but thank god it's not much. This site and 4Chan are still decent.
You are getting down voted for your sweeping generalizations, but I agree Reddit has declined in quality over the years. So has HN. 4chan has also declined somewhat but its brashness serves as a filter and is a barrier to entry for many people. People who have been around 4chan for a while know the offensiveness is essential to preserving the culture.