The logical fallacy I see used most is false equivalence, most commonly in the form of strawman. Although it's used mainly in the "free speech for nazis", "feminism is cancer", and anti-SJW hysteria crowd that the snake oil salesmen who used to sell loose change dvds are now servicing. For example example a Scottish court fining a youtuber for making jokes about gassing jews is presented as equivalent to a government jailing/murdering a person for expressing an opinion. Or a woman asking to hire more women (thereby reducing the number of hired men) is portrayed as equivalent to removing an ethnicity entirely through genocide. But the people whose entire arguments are based on logical fallacies commonly have prepared tricks to counter people who point out their logical fallacies. For example a youtuber who uses strawmen all the time made a video calling people who accuse him of strawmaning "straw crows", which successfully made his followers totally immune to people pointing out his logical fallacies.