The article mentions this briefly, but Tunisia just wasn't as important to the French as Algeria was. To France, Algeria (at least the populated northern coast of it) wasn't a colony, it was Metropolitan France--it received full representation in the French legislature, for example. (Note that this was in practice limited to the French settlers in Algeria, as the natives were largely excluded from civic participation--not unlike the apartheid system in South Africa). Given that native populations weren't particularly well-treated, especially after their lot failed to improve despite being the major backbone of the Free French Army in WW2, it's not much of a surprise that they resented French rule and chose to become independent.
And quite like the settler colonies of other countries in Africa, the settler minority who held power in Algeria weren't particularly inclined to give it up to the majority they largely felt beneath them. And since it was a severe insult to national pride to let a core part of France become independent, the French government resisted to the point that it literally broke the government (the Fourth Republic fell because of it, leading to the Fifth Republic).
And quite like the settler colonies of other countries in Africa, the settler minority who held power in Algeria weren't particularly inclined to give it up to the majority they largely felt beneath them. And since it was a severe insult to national pride to let a core part of France become independent, the French government resisted to the point that it literally broke the government (the Fourth Republic fell because of it, leading to the Fifth Republic).