The singer-songwriter posted a video on her page explaining why Grande's deflection of blame for her doughnut-licking scandal onto obese Americans is indicative of greater societal problems.
"When I saw her go right in for that apology it upset me, because it really was taking the focus off of the fact that she licked some doughnuts in a store – and that's f------ gross – and kind of threw fat people up as the reason that everything's awful," said Tonjes.
"I'm not saying that she doesn't have a great point about the food industry, or the quality of food that we have […] but if we want to sit here and believe that it's just the fat people in America who are [eating unhealthy foods], it's not," she said. "People are shocked that I don't sit all day on the couch and eat pizza, but you know what, sometimes I do, because sometimes everybody does."
The Los Angeles-based musician went on to explain the larger issues she has with societal attitudes towards people who are "fat."
"If I were 120 lbs. eating a pizza in my underwear on Tumblr, I would be 'quirky' and 'cute' and 'real,' but if I'm 300 lbs. and I'm eating pizza in my underwear, people are like, 'You're killing yourself,' 'You're disgusting,' 'You're everything that's wrong with America,' " said the 29-year-old.
"We live in a culture that glorifies food, but then we hate the people that we think are representative of that sinful desire for food," she continued. "I just wish that people remembered that fat people are people."
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Tonjes hopes her video – which currently has over 50,000 views – opens up a dialogue about how people view those who are overweight.
"We judge people based on what we think they do, and that judgment changes based on how they look," she tells PEOPLE. "I just wanted to highlight the hypocrisy of some of the things that happen when we start going in this direction of 'Fat people are bad,' 'Fat people are evil,' as if that's the problem. I hope that people watch [my video] and it sparks conversation."
Tonjes hasn't been surprised by the impassioned commentary her video has already generated – both supporting her and critiquing her views.
"I knew that it was a topic that people feel very passionately about on both ends," she continues. "I know that it's a very hard message to swallow."