There is a difference between merely engaging in positive thinking and undertaking positive action. On its own thinking is merely an interior act, and only when connected to positive actions does it create new realities.
Look at issues like slavery, women’s rights, democracy. Changes in each of these were fueled by anger channeled towards action that led to change. I like to call this productive anger. It’s not about rage, rather it’s about what some might call ‘righteous anger’.
Productive anger that generates positive action has led to great changes in world.
I suppose it’s what you do with the positive thoughts that matters more than merely thinking them. One of my old school mottos was:
In deed not word
1 John 3:18
And a famous slogan of the Suffragette movement was:
“‘Deeds, not words’, was to be our permanent motto,”