I see this mistake often in online exchanges. I'd like to help spread the term I believe John Corvino coined.
One commits the Fallacy of Perverted Analogy when one misreads an opponent’s analogy to make a far more sweeping comparison than the opponent needs or intends.
A "Some people feel disgust at the sight of men kissing. But it doesn’t make sense to condemn a person merely for feeling disgusted. You probably feel disgust when you think about some sex acts too — for example people who enjoy eating shit"
B "It's your comparison of two men kissing to eating shit that's disgusting. It's bigoted and makes no sense. The two things are worlds apart!"
B "You use the services that the state provides. That means you consent to being taxed."
A "If a slave accepts a meal from his master does that mean he’s consented to his enslavement?"
B "You're comparing paying taxes to being a slave?! This conversation is over."
In the examples speaker A is not suggesting that the things being compared are similar in every way, or even most ways. They believe they’re similar in a limited way that’s relevant to the topic of the discussion.
B might be able to show differences between the things being compared that are relevant to the conversation at hand. Those differences might make the analogies invalid. But just pointing out that differences exist, even large differences, is not enough to dismiss the analogy.