The Magpies came from behind at Loftus Road to register a 2-1 victory and confirm their Premier League status for another year.
There have been reports that the sizeable French-speaking contingent in the dressing room are at odds with their colleagues, but Williamson feels that their weekend performance shows such talk is wide of the mark.
"There has been a lot said about it, a lot of speculation but you could see the commitment and the euphoria after the game between the players," he said.
"There is a lot of passion now and we are a very tight bunch.
"Maybe a lot is said about it in the media but it is all rubbish because the lads are tight, everyone doing it for themselves as much as each other.
"There is a lot of relief in the changing room and with the fans. It was a tough, tough game. We had to show resilience and character and I felt that is what was needed."
Newcastle's fans have endured a rocky season, particularly when compared to the previous campaign when they clinched Europa League qualification.
"As players, maybe we have not hit the heights both personally and collectively but we just want them to know it wasn't through a lack of effort and commitment," said Williamson.
"Hopefully we showed them that and we can enjoy the last game, the fans can have a great day out and we can try to get a big scalp against Arsenal.
"We've got the strength and depth and whether we add a few in the summer or not that is down to the manager, but I feel we have all the quality and the attributes to replicate what we did last year.
"I know it has been a tricky, tricky season but hopefully with a bit more of a rub of the green we can do what we did again."