The original statement is a generalisation, and generalisations are often wrong.
On my last three tours in France I met four French tourists (two solos and a tandem), all charming people; three used a trailer and one front panniers only. The tandem couple who used a trailer were very insistent that we were going about things the wrong way with only two panniers on a tandem (credit card touring) and that we should use a trailer. The three people we met who used trailers were out on unencumbered bikes, and the details of what sort of tours they did and what their luggage arrangements were came out in conversation, so had we passed them without a word, they would have added to our perception that the French are not great cycle tourists.
What I've just said is a generalisation based on not very much, so, I'd suspect is the statement in the magazine quoted.