Two similar edge-cases that I still have no idea how to handle
There are two particular kinds of answers that I still have absolutely no idea how to vote on. Those being answers that are objectively incorrect and answers that are toxic and/or propose solutions that are deeply flawed and problematic.
For the first case, there are answers like this one which describes the notation "1d-4" objectively incorrectly, or this one which claims Rogues can only get Sneak Attack once per round. Both of these answers currently have a single delete vote.
For examples of deeply flawed answers, there's this one:
I hate to sound crass here, OP, but there's a reason that you don't date your fellow players, and you're discovering it. Love tends to make one see something in another that other people don't, just by its very nature. This means that even if you're best friends with someone, they might end up being in love with someone you despise, even though that seems bizarre. Not to mention people tend to treat games differently. Your friend's husband obviously doesn't understand the point of the game, or doesn't care.
The lack of perspective from the "innocent" member of the couple is what creates the rift in the table. You have to discuss this right now and as directly as possible before negative sentiments become more deep-seated and someone explodes. You will not get lucky and have your GM divorce her husband suddenly or something equally unlikely. The worst case scenario is that you leave the table quietly, but your friendship will remain intact, while a full-table drama episode could end up with everyone hating each other.
Beneath this answer is the following comment:
This attitude is condescending and toxic. Every couple I've ever gamed with has been terrified that their very existence could ruin the game, to the point that they impose pointless handicaps and limitations on their gaming habits. Couples have never been a problem in any of my groups, but this attitude toward them has. This querent's problem is a challenge faced by individuals, not an inevitable result of couples gaming.
And for another example, there's this one
[...] Handicap his character forcing him to develop his RP skills. This can be done a million different ways. ex: forced polymorph, death with new creation requirements, equipment loss, forced individual diplomacy, Stat losses, unusual poisoning/enchantment, charmed/cursed equipment, or just have the other players kill his character if he is doing "evil things" and causing the party harm.
There are a million thanks that would case a player to start questioning his actions. And if they complain let it be known, this isn't a video game. Your actions and or inactions have consequences.
Beneath this answer is the following comment:
I have intentionally not deleted this, as I believe (at time of commenting) -7 downvotes is more instructive than no answer. This is an abysmally wrong answer, however.
Many of the site's lowest scoring answers fall into one (or both) of these categories. Furthermore Meta Stack Exchange even has some guidance on this kind of stuff:
We even have a relevant Meta question ourselves:
This has a few answers as well as this comment:
Sometimes keeping a bad answer is quite helpful: it's very instructive in how to not use the system.
I know there are people who think terrible answers, in at least some cases, should be kept around so that their highly-negative scores can showcase what not to do. But I've also seen a lot of answers that fit into one (or both) of these categories get deleted and I've seen a lot of arguments about how deleting these is actually the best thing to do. There's a lot of information on these with all sorts of proposed methods of handling them.
That all said, I don't expect this answer will be helpful for deciding whether an answer should or shouldn't be deleted. I wanted to talk about a particular part of that decision-making process that, even after a sizeable amount of time here, and even after having given this considerable thought, I still have no idea how to vote. People will disagree when it comes to these, and that's perfectly fine.
I'll end with probably my biggest takeaway from looking into these kinds of answers: deletion voting is not a science, it's not an exacting process with hyper-defined rules and objectivity; uncertainty is unavoidable and that's okay. Look around, ask around, figure out what other people think, and build up your own ideas about it. Trust me, there's a lot of discourse on this and just when you think you've found all seven ways to handle question X, you'll find somebody suggesting three completely new ones.