Why did the reservationists believe that some provisions of the league of nations were dangerous?

The correct answer for this question is this one:

The League of Nations was formed and was turned down applied principles of of progressivism to foreign policy.

Ideas of free trade, democracy, and self determination sprang up from the same ideals Progressive reformers supported within the u. s.

They declared that the foreign policy of a democratic nation should be based on morality not just on what was best for that nation"