This statement can be true for many reasons. For instance, different situations may involve different people with different personalities. Or they might involve different levels of urgency. When situations differ in these ways, they may well call for different leadership styles.
A style that is effective with one subordinate may not work with another. One subordinate may respond well to being pressured while another may need reassurance and kind words. Clearly, different styles would be needed in dealing with these people.
A crisis might call for a different style than more normal times. In normal times, one can be patient and work for consensus. In a crisis it may be necessary to be autocratic and demanding. These are different styles as well.
In these ways, different leadership styles can be more or less effective in different situations.
Yeah the statememt is very true. I can give you a very simple example, For instance if one country requires aggressive type of leadership and the leader is aggressive so that country will go in a right direction.
But if we change the situation and that country requires non- aggressive type of leadership and the leader is still aggressive so that would be the worst scenario for that country.