The scathing attack Tuesday from a member of China's organisation overseeing relations with the island comes amid heightened tensions between Beijing and Taipei after the election of Taiwan's first female leader, Beijing-sceptic Tsai Ing-wen.
Tsai's office and the ruling DPP declined to comment on the remarks, but enraged politicians and citizens openly voiced their displeasure.
"It's such a ridiculous remark and discrimination against single people. Everyone has the right to choose his or her lifestyle by having partners or staying single and that should be respected," DPP lawmaker Yeh Yi-chin told AFP.
"Such a personal attack is extremely improper. It's gender discrimination and we strongly oppose such remarks," said Wang, from the Beijing-friendly KMT party.
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The remarks from Wang Weixing, a military analyst and a board member of the Association for Relations Across the Taiwan Straits, claimed that Tsai's politics were affected by her status as a "single female politician".
"In political style and strategy, often she tends to be emotional, personal and extreme. In terms of political tricks, she considers strategy less, tactical details more, and short-term goals are paramount, while long-term goals are less taken into account," Wang wrote.
"Why doesn't he criticise a bunch of married male politicians who are having extramarital affairs? (He's) a chauvinist pig who hurts gender equality," wrote one post on the Facebook page of Taiwan's Liberty Times newspaper.
"It is a crime to be single? Such a remark only shows the world how perverted China is," wrote one message on the Apple Daily's website.
Another blasted: "China is so barbaric."
Tsai, from the Beijing-wary Democratic Progressive Party (DPP), was inaugurated last week, succeeding Ma Ying-jeou of the Kuomintang (KMT) who oversaw an unprecedented rapprochement with China.
Although Taiwan is self-ruling after splitting with the mainland in 1949 following a civil war, it has never formally declared independence and Beijing still sees it as part of its territory awaiting reunification.