I'm sure french athletes would dope (and did dope) as much as anyone else, but the french public opinion just does not stand for it, when push comes to shove.
Virenque was a hero. Finally, a potential replacement for France's long lost champions; even though he was dumb as a rock with too big a mouth. And then the truth came out. The disappointment was intense and very bitter.
Virenque wasn't talented, he was a cheat.
It was like "not only are we no good and a second-rate cycling country, but on top of it we are cheats, and seen as cheats by the rest of the world". Nope, Virenque, who already wasn't very likeable to start with, didn't really survive that one.
If you doubt this, just take a quick look at Henry's handball vs Ireland to qualify for the world cup. The backlash has been massive in Ireland about it, but it has been nearly worse in France.
The french have a lot of defects, but the "average french" does not like or condone cheating or doping, in any discipline. The french enjoy their moral high ground very much. (popularity of the tdf in France is at an all-time low since it started in 1903; I'm not making this up and it's not hard to figure out why)
I'm quite sure that if the french riders are clean atm, it's because of the fear of public retaliation, rather than anything else.
(you could produce Anquetil as a counter-example, I suppose, but Anquetil is in a class of his own)