Armistead, 23, said she buttoned her lip when Pat McQuade, president of the world governing body of cycling (UCI), shook her hand at the start line.
"It was the kind of moment where you kind of want to say 'Let's sit down and have a conversation after this,'" Armistead said.
She made the comment after being asked at the post-race news conference about equality for women in the Olympics, and how she felt about racing in an Olympic field of just 66 when she is used to competing in much larger fields.
"It's something that can get overwhelming and very frustrating, the sexism that I experience in my career," she continued. "But it's something that as an elite athlete that you just get used. At the moment there's not much I can do to change it but after my (athletic) career I hope to."
Asked to elaborate on the sexism, she said it was "obviously just a big issue in women's sport."
"The obvious things like salary, media coverage, just general things that you have to sort of cope with in your career. Like I say if you focus too much on that, you get very disheartened and I try to focus on the positives."
Armistead said plenty could be done to improve the problem "but certainly I think we could get more help from the top — which is the UCI. Just certain things like forcing perhaps pro teams to have an equivalent women's team et cetera, but I don't want to focus too much on the negatives really."
Asked whether athletes should use the courts to force such changes, Armistead said "it's something I'm not qualified to even think about. I'm just a cyclist.
"Obviously if we join together, we've got a stronger stance and I think it's something we do need to do. But the problem is we are elite athletes training every day trying our best every day. So it's very difficult to try to come together when I've been at home five weeks this year, to try to tackle that massive issue. Unfortunately it's something that will take a while to change."
Armistead was also happy to address a question on being a vegetarian.
"I've been a vegetarian since I was about 10 years old, just simply because I don't like meat and I can't sort of get my head around eating a corpse."
Armistead also lamented losing her "lucky" sunglasses — which were in Team Britain colours — during the race when she had to take them off because of the rain.
A British reporter later asked her if she wanted the glasses back.
"That would be nice. But it would be nice if Oakley gave me a few more sets maybe," she said with a laugh.
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