I was just in discussion about fallacies and thought I would jot down my opinion on the issue.
In my opinion, the primary reason for studying fallacies is to improve one's own reasoning abilities. When people accidentally make a fallacy in their system of reasoning, they end up with contradictions that undermine their efforts.
My observation is that the accusation of fallacy comes off poorly in argumentation.
I believe that classical thinkers got it right when they made a firm distinction between logic and rhetoric. We use logic to make sure our ideas are sound. We engage in rhetoric to express our ideas.
As people are instinctively competitive, it is natural to desire a bag of rhetorical tricks that can trip up one's opponents. Since the discovery of a fallacy in a system of reasoning can be devastating, it is tempting to use the accusation of fallacy as a rhetorical trick.
My observation is that such tricks rarely work in practice. More often than not the person making the accusation of fallacy comes off as small minded.
In a surprisingly large number of cases, the person quick to use accusations of fallacy as a rhetorical trick is wrong in their analysis of the fallacy.
For example, if you think such and such while I think so and so and I accuse you of a fallacy because such and such is logically incompatible with so and so; then my accusation of fallacy simply shows my ignorance of logic. Our argument about such and such v. so and so will be rife with contradictions simply because such and such and so and so are logically at odds.
If you look at the text of any substantive argument; you will find the text full of contradictory statements simply because there was a substantive disagreement. Person A says "X is True." Person B say "X is False." The transcript of the argument has the contradiction saying A is true and false.
The proper use of logic can help in a dispute in clarifying points. For example, if we agree on points A and B but disagree on point C, then your pointing out that my version of point C logically contradicts point A; then you've got something. For example, if two US Representatives are arguing about a law and Representative A points out that the proposal by Representative B violates the accepted understanding of the Constitution, then Representative A made a substantial blow against the opposition's argument.
In the political realm, a candidate might make inroads against the opposition candidate by pointing out logical fallacies. The gains are tenuous. The presence of a large number of fallacies in a candidates writing might show that the candidate is not authentically engaged in the reasoning process. This is especially true when one finds a candidate changing positions on a issue for the audience. A candidate who is pro-choice when speaking at a Planned Parenthood fundraiser on Monday, then pro-life at a church fundraiser on Tuesday can be proven a rogue by comparing the speeches.
If you find a person is intentionally using fallacies, misinformation or other negative tricks to fool people; then you do the world a favor by pointing out the dirty tricks to the people being tricked. Pointing out misinformation given by others can help people avoid mistakes. Finding logical errors in the works of errors does not mean that one's personal philosophy must be better. Popper did an eloquent job showing errors in the works of Plato, Hegel and Russell, yet that does not mean Popper's world view is any better.
The accusation of fallacy might show weakness in the opponent's reasoning. It rarely changes mass opinions on a topic. In some cases it shows weakness in the accuser's ability to reason.
If I hold premise A, and you hold premise B and the two premises are at odds with each other, then my accusing you of fallacy does nothing more than show that I am incapable of seeing an issue from more than one perspective.
When people begin toss accusations of fallacy at people simply for having different opinions, while turning a blind eye to faults of friends, they are not engaged in reasoning. They are simply engaged in name calling and insults.
My conclusion is that one should engage in the study of fallacy primarily to improve one's own reasoning ability. For that matter, one should not engage in the study of fallacy before developing an appreciation of Sound Rational Thinking. After all, using accusations of fallacy as a rhetorical trick is often nothing more than a sophisticated means of name calling and insults.