The "Bad at Love" star, who also identifies as a bisexual, was stunned by the narrow-minded remark she spotted online, and decided to take aim at the writer, tigerbob.
He wrote: "#MileyCyrus splitting and allegedly cheating on Liam with a woman confirms that you shouldn't date bi people. Not offensive, just true. Bi is greedy and never satisfied."
Halsey tweeted: "Hey tigerbob. Doesn't surprise me that ur saying this and ur page has u crying about Brie Larson too! Stop being afraid of women who aren't afraid to do what pleases them and not other people."
Miley recently made it clear that marriage had not turned her straight in a recent interview, stating, "I'm in a hetero relationship, but I still am very sexually attracted to women."
The singer's representative broke the news that she and Hemsworth had split on Saturday (August 10), hours after photos of Miley kissing vacation companion Kaitlynn Carter were published online.