If their post is truly idiotic and a time waster, then it will drown in obscurity all by itself.

I see you're new here. Perhaps you're unfamiliar with the concept of "the tragedy of the commons"?

While I don't think that calling people idiots will make the subreddit better, I don't think calling people idiots when they actually are idiots will do the subreddit any particular amount of harm, either.

The truth is that some people are not cut out to be sysadmins. It's also true that literally saying simply "you're an idiot" and leaving it at that is not an effective response. But people who clearly don't have what it takes to do their job and are asking /r/sysadmin to keep them afloat need some constructive but appropriately harsh criticism to wake them up and set them straight.

I'm not here to coddle people, and it does a disservice to ask those of us who know what we're doing and don't need our hands held to treat the incompetent with kid gloves. It's one thing if I work with someone. Then I'm being paid to take some responsibility for making sure they have the tools they need to do the job. I also have someone to report to if they consistently demonstrate that they are not able to do their jobs. Here I'm giving advice and assistance of my own free will, and I'll do it as I damn well please.

Your advice to ignore the idiots instead of insulting them works equally well going the other way: if you don't like my approach to dealing with idiots, ignore me. If you think ignoring something is the best way to address it, then please feel free to do so as often as possible.