This website isn't going to change its reputation. It's really as simple as that. Most of the people here are very critical of the games we play. Most of us take established lore in games very seriously. We're what casual gamers would call "nerds" because of how much time we put into loving video games, reading lore, appreciating worlds, and so on and so on.
People don't like NMA because it took a dump on FO3 when it came out. A lot of people, myself included, were young and didn't think FO3 was that bad. For a lot of gamers, FO3 was their first open world experience besides Oblivion. That includes me as well. We all collectively sucked Bethesda's dick and refused to let go. To put FO3 in perspective, I was 13 when that game came out. I'm 20 years old now. So when we, this new generation of "RPG" players, saw NMA bashing FO3, we promptly called them out as cynical old farts who were too attached to PC games from the 90s.
I wasn't really a part of that last crowd, but I probably would have defended FO3 to death back in the day. Soon after FO3 though, I played New Vegas. Then I played the original FO games. And I've never looked back. In fact, nowadays I can't even replay FO3, it's that bad to me. Yet I've managed to sink 500 hours into New Vegas.
So I guess to answer your question, the reason why this website has its reputation is a lot of people hated how they bashed FO3, and the reputation has stuck in their minds. Now those same people who hated this site for bashing FO3 hate this site for bashing FO4, alongside an entirely new generation of people waiting in line to suck Bethesda's dick.
I hope I made a good enough analogy for you.