A good post about the kinds of arguments people use online, including tactics which are about the argument itself or some of the people involved in the argument, as opposed to being about the argument’s supposed topic.
You should know this to, one, avoid pointless “debates” where no actual issues get debated, two, to improve your own debate style to focus on the issues that need to be debated most, and, three, to see when others are merely acting like they’re debating without actually debating the core issues the debate is supposed to be about.
To your second point, this is actually a major problem of debates from a psychology stand point. Unless people are willing to change their beliefs, debates actually strengthen their belief in their previously held ideas. It is useless to debate someone that is not willing to change their mind.