Re: Random thoughts on this sad situation
That's EU rules
No, it's French rules, and I have the "Carte de Séjour permanent" to prove it (I moved here before the EU was created). 5 years at first, then you have the right to permanent residence which you keep unless you're absent for more than 2 years.
Permanent resident status is what gives you the rights of a native to things like benefits and healthcare, and to get citizenship
Salaried employment gets you the rights to benefits and healthcare. French citizenship is a different matter. Make a request today and you'll get a date for an interview in 2020 (and that's not just for UK citizens post-Brexit).