How can anyone be a Petainist nowadays considering the role of the Petain regime in deporting a quarter of France's Jews to their deaths? The Petain regime wasn't actually obligated to do this (AFAIK, the 1940 armistice agreement between France and Germany does not say anything about Jewish deportations) and yet it nevertheless did this.
Indeed, in some cases, the Vichy government exceeded Germany's demands in a calculated attempt to please the occupiers.
They did so when arresting foreign jews, who were the first victims of Pétain's anti-semitic policy.
On the other hand , more than 90% of French jews survived, the highest propertion in all occupied Europe.
Even though the deportation of Jews wasn't part of the Armistice deal, the German demands came later.
The infamous "Rafle du Velodrôme d'Hiver" in 1942 was a disappointment for the Germans who officially complained to the Vichy authorities, as the number of people actually arrested was far smaller than what the Germans had demanded and expected.
While some Vichy officials and police were eager to get rid of Jews, many others stalled, passed on information, warned people etc, which allowed the vast majority of French Jews to survive the war.
As for Pétainist people, hard to say, but some still believe he was a hero an did a good job at protecting France, out of hatred for socialism, foreigners, or jews or parliamentary democracy, or because of idealised fantasies about the past, lack of information, refusal to accept reality and facts about Pétain and his regime, etc
The Pétain years have been a complete mess for 80 years now, still dividing people whenever the subject comes up.