What role did Colonialism play in the development of pidgins and Creoles?

Pidgins are more direct results of colonization. When you have an indigenous population and a colonizer who speak distinct mutually unintelligible languages, a simplified version of language mixing Words from both languages is much more effective at communication than the more complex nuances of either native language. The most prolific pidgin is probably Tok Pisin, an official language of Papua New Guinea which developed between the British and a variety of New Guinean tribes.

Creoles typically developed among the African slave populations in the Americas as they were trying to find a way to communicate with each other and also with the dominant White population. (They had difficulty talking to each other because they came from different parts of Africa, so their languages were similarly mutually unintelligible.) This multidirectional confluence resulted in creoles being uniquely developed by different African communities in the Americas.

With the exception of Tok Pisin and, possibly, Haitian Creole, pidgins and creoles are seen as being inferior modes of communication and most people who seek to show that they have class try to speak the "pure" language. This is similar to the way that most people who speak an Arabic dialect will only write in "proper" Arabic and would find it "class-less" to write their dialect.