They didn't remove the bolts for "leave no trace" reasons. They removed them because the style they were put up was considered "poor climbing ethics". They felt it could go "free" and on gear.

This would have made the summit unobtainable to all but the strongest climbers in the world... Which would have upset many people who had traveled far and spent a lot of money to attempt the summit.

Alex Honnolds "climbing gold" podcast has like a 3 part series on this history if your interested to learn more.