Except it wasn’t the legos causing the trouble. It was a few kids. Instead of correcting those kids that were being selfish jerks they blamed the toy and punished everyone. Well those kids will still be selfish jerks, the problem remains.
Removing the toy that is the focus of a lot of interpersonal drama is (sometimes) a quick way to diffuse the immediate conflict. Then talking together about how different people are feeling in a particular circumstance and getting group feedback on ways to solve problems constructively is the way to help kids improve at the skills they are lacking.
If all possible source of conflicts are removed than when significant conflicts are going to arise and be learned from? This is self-contradicting.