Defending champion Vingegaard's performances have come under tight scrutiny after the Dane pulverised his rivals in Tuesday's individual time trial to strengthen his overall lead.
Plugge told L'Equipe that Vingegaard and his team's success was due to extreme attention to 'details', saying none of the riders drank alcohol.
"We were with a French team at our hotel during the rest day. We could see riders drink large beers... Alcohol is poison and when you're tired (and you drink) it makes you more tired," Plugge said.
Groupama-FDJ were the only French team sharing the same hotel in Saint Gervais on Monday.
"Who does he think he is? Frankly, it's an exceptionally vile attack on his part... Let him keep his mouth shut! I don't intend to see him, I don't care about him. I'm not going to go and see him. I'm angry, it's pathetic," the Groupama-FDJ team manager Marc Madiot said.
"I don't watch what he puts in his riders' bowls."
"On each rest day, we have an aperitif (light snack) before going to dinner, it's an opportunity to strengthen the ties and pass on positive messages or refocus (some riders) if necessary," sports director Philippe Mauduit told Reuters.
"Everyone orders the drink they want, and the guys (riders) are so tired this year that they're not fooling around," adding none of the riders had drunk alcohol on Monday.
