Let me give you an example of why this is a weak argument, and bear in mind that I say this as someone that has lived and worked in France for the last ten years.
I'm going on 40. I'm not married, and I won't be having kids. From your list of benefits:
* although I also didn't have a student loan, it wasn't thanks to French taxes.
* I don't / won't have kids so their subsidised schooling does nothing for me individually
* health insurance. I'm still young enough that I don't have any major health problems, although of course, insurance is also protecting me from accidents and what not, so I am getting some benefit from this. Concretely though, I haven't as yet got much more than a few courses of antibiotics paid by the government in 10 years.
* safe enough? Pretty much the only reason you don't have gated communities in France is because all of the places that rich people live in have been there for hundreds of years. If they could figure out a way of doing it, the 16th arrondisment of Paris would totally gate itself off.
* unemployment - yeah, I'll give you this one. I'm almost tempted to try and get myself fired, just so that I can spend three years funded by the taxpayer to start my own business. (not really, but that idea certainly removes any fear I have of getting fired).
* retirement - no reasonable person believes that people of my age or younger will get much of a retirement pension. If you're not taking steps to guarantee your own retirement at this point, your going to get a bad surprise at the end of your career.
* I'm not having kids, so parental leave gets me nothing
* massive tax breaks for nannies etc? well, in the sense that you can more or less claim their salary off your salary for tax purposes, I suppose that's true, provided you're actually making enough money to be able to take someone on in the first place (I personally have a housecleaner, but my flat is so small that she only works for 3 hours a week - at her hourly rate, that works out to a tax saving for me of around 1000E a year. Not exactly massive).
As always with government subsidies, they are just not as flexible as giving people the money and letting them decide for themselves how they are going to spend it. My salary is suppressed to pay for a whole lot of benefits that I personally will never see. There is a case to be made to limiting government subsidies to oly those activities that the government can do cheaper than anyone else (maintaining roads, fire department, police department).
So why am I still in France if the deal is so raw? Well, personal reasons, and I'm also enough of a lefty that I do see value in providing good education, public transport and health services to everybody, so I don't resent those taxes. But I'm willing to bet that a lot of people would decide otherwise if they had the choice.