I have played worse games that have better reviews than this. Bethesda made a very risky move by taking this game online. There is a huge cult following for Fallout and Bethesda Game Studios have exclusively made Single Player games.
As bold and risky this move was, I think they did a pretty good job. I did play for about 30 hours when it first came out and am just recently getting back on with a new character for Wastelanders. The NPC's really make this feel like just another Fallout game which is what I want. The first go around, it was really hard to get into the story, the world felt so empty and I was not even going to try and find a group of people to play with around my schedule (family and work). Now, it doesn't feel so empty, fighting raiders on my way to start a new quest brings back a lot of fun and nostalgic moments from Fallout 4.
I get the hate, it was expected with such a risky move. I think some people are taking it too far. Reading a lot of the negative reviews, it seems like people are upset because it wasn't what they expected and that doesn't make a game bad and deserve a one star review. Honestly though, being a part of the online community, like reddit, I have been surprised with how active this game is. I think the devs are doing a great job and this game has a bright future.