To start off, you could write entire essays delving into this topic. Everything I’ve written in my reply is very condensed, so if you feel something lacks nuance, it’s probably to keep it brief rather than because I thought it is “THE ONE AND ONLY ANSWER”. Here goes.
Religious freedom has two key parts: freedom of religion and freedom from religion.
Which of these holds prominence is different depending on the secular country you’re in, and usually has a lot to do with the historic path that the nation and dominant culture took to become secular.
In France organized religion had an authoritarian position in society, dominating it for more than a millenium. It took literal centuries of bloodshed and more than one revolution to put an end to that dominance. That is the origin of those laws. The lessons behind their making were learned at the cost of many lives, and personally I don’t think that such laws should be ripped up without proper consideration.
Religion, particularly the organized kind is designed to spread and exert power over people and societies. Furthermore, unlike many other things such as ethnicity, sex or disabilities, it is a strongly held personal belief, which is a choice. Yes, there is some nuance there, but it is mostly based on convictions and antiquated traditions, much like the old republican laws themselves perhaps.
A question follows, should a person based on an arbitrary strong personal conviction be granted special treatment?
If yes… then I argue that this should not be limited to “religious” beliefs. The only thing that makes those particular sets of beliefs special, after all, is tradition and mass adoption, much like our own cultures. So, lets consider some other minority beliefs. Should a furry who “needs” to wear wolf ears be allowed to wear that? A sikh their turban? A pastafarian their mandated colander? What if someone strongly believes that they can’t go outside without wearing a CocaCola branded cap (mmm delicious ad revenue)?
From what I’ve read on the topic, this take seems misguided at best or outright wrong at worst. Historically, secularism in France has been a primarily liberal/socialist/anti-monarchist pursuit.
French secularism has its origin in the French revolution, half a century before Algeria came under French control. Religious institutions were viewed as a part of the aristocratic establishment and the concept of laïcité was introduced under the revolutionary era and entrenched (along with concepts such as freedoms of thought, expression & conscience) during the Napoleonic era. Further progress in this direction was not made by imperialists, but rather revolutionaries after bloody conflict (the French commune for instance) and generally steps were taken to repeal them when conservative/monarchist governments dominated.