Bernie Ecclestone says he cannot see why a "good-looking" woman standing next to a driver at the start of a race could be "offensive".
The 87-year-old tycoon said it was a sign the UK was becoming "prudish".
It came after Liberty Media, the sport's organiser, said the custom of using women on start lines was "clearly... at odds with modern day societal norms".
The women are often seen carrying the drivers' standards which indicate their race numbers and their location on the starting line.
They also often line the route that the top three drivers take as they head to the podium at the end of a race.
:: 'I'm proud of being a grid girl - don't ban us'
Ecclestone told Sky News: "These girls did nothing harmful to anyone.
"We might as well say we do not want people going to fashion shows. They were smartly dressed.
"We have people saying it was going in darts, but that's a different type of sport, if you call it a sport. I thought people enjoyed seeing the girls and they are necessary really.
"When the team driver wants to get on the grid, it is much easier for them to know their place, where they are going to stop than hope they get it right and hope the teams were helping.
"It took a lot of time and stress from the teams."
He also said, assuming it did objectify women, he didn't "remember any of the girls being forced to do it".
He went on to deny that grid girls would be wearing shorter skirts than they would do in any other situation.
Ecclestone, who ran F1 for more than three decades, told The Sun earlier: "The country at the moment is getting a bit prudish.
"You should be allowed to have grid girls because the drivers like them, the audience like them and no one cares. These girls were... part of the spectacle.
"I can't see how a good-looking girl standing with a driver and a number in front of a Formula One car can be offensive to anybody."
It is not the first time Mr Ecclestone, who became a billionaire as a result of his investment in the sport, has made statements about the participation of women in F1.
In 2016, he told an advertising conference that female drivers would "not be taken seriously" in Formula One and they are "not physically" able to drive cars that fast.
Several so-called grid girls have leaped to the defence of those who stand to lose their jobs as a result of the move.
Lauren-Jade Pope, a "grid girl and promo model", tweeted: "Because of these feminists, they've have cost us our jobs! I have been a grid girl for 8 years and I have Never felt uncomfortable! I love my job, if I didn't I wouldn't do it! Noone forces us to do this! This is our choice!"
Rebecca Cooper, another grid girl, said on Twitter: "If we don't do something to stop this where will it end? No grid girls, no cheerleaders, female singers being told what to wear on stage, no models in magazines?! I'll fight for my right to choose what I wear, where I work and to keep a job I love. I'll #fightformyrighttochoose".
The organisers of some of darts' biggest tournaments, the Professional Darts Corporation, also recently decided to stop using walk-on girls.
A Sky News online poll asking people if they thought walk-on girls should be banned from all sports found 17% in favour and 83% against, after nearly 13,000 votes.