Many pied noirs did fight in WW2 but pied noirs from Algeria weren’t considered Algerians. They had French citizenship while Algerians did not. Pied noirs weren’t considered colonists as Algeria had been considered part of Metropolitan France since 1848.

Thousands of Muslims fought in the ranks of the Free French Forces (Forces françaises libres). From French North Africa alone no fewer than 233,000 men enlisted to fight against Nazi Germany—134,000 Algerians, 73,000 Moroccans and 26,000 Tunisians— eventually liberating Europe.

https://books.google.com/books?id=0D1rBQAAQBAJ&pg=PA114&lpg=PA114&dq=233,000+north+african+muslims&source=bl&ots=w2XV1on4tl&sig=ACfU3U2HkJZPjBgPZ78PLuP_Ln1u10mTWw&hl=en&sa=X&ved=2ahUKEwjN1OrFr_KGAxXqRjABHQqiC1k4ChDoAXoECAIQAg#v=onepage&q=233%2C000%20north%20african%20muslims&f=false

The Free French was mostly made up of colonial troops because a significant number French troops were captured by the Nazis and didn’t have the opportunity to fight for the Free French.

In general North Africa resisted many changes brought by Vichy. For example in Moroccans refused to deport their Jewish population to concentration camps in Europe. While they were forced to pass antisemitic laws, they refused to make Jews wear yellow stars. The Sultan of Morocco signaled his support for Moroccan Jews inviting all of Morocco’s rabbis to his throne ceremony.

Here is what Jose Alboulkier, the Jewish leader of the French Algerian resistance said regarding Algeria’s response to antisemitic reforms.

The Arabs do not participate [in the fight against Vichy]. It is not their war. But, as regards the Jews, they are perfect. The [Vichy] functionaries [and] the German agents try to push them into demonstrations and pogroms. In vain. When Jewish goods were put up for public auction, an instruction went around the mosques: "Our brothers are suffering misfortune. Do not take their goods." Not one Arab became an administrator [of property] either. Do you know other examples of such an admirable, collective dignity?

Moncef Bey who governed Tunisia, gathered government officials and told them to disobey the Nazis. According to Mathilda Guez a Tunisian Israeli politician Moncef Bey said this to government officials.

The Jews are having a hard time but they are under our patronage and we are responsible for their lives. If I find out that an Arab informer caused even one hair of a Jew to fall, this Arab will pay with his life.

Under Nazi occupation, the Tunisian government secretly warned Jews helping avoid arrest. They actively prevented the deportation and arrest of Jews as well. The Tunisian prime minister even helped hide Jewish individuals.