Significant explanation is often given. Extensively so. I know I have spilled a whole lot of virtual ink on this stuff in pretty much every thread I try to talk about this stuff. Others have spilled far more.
Sure. But in this context, knowing your audience includes knowing the medium. If you are sitting in a room with the same group of people for two hours, having a conversation everyone is focused upon, and only one or two people come in or out, you can probably get away with spilling that ink once. In the next discussion, if there are new people, you'll have to spill that ink again.
Now consider the message board medium - we have asynchronous communication among a varying group of dozens over the course of days during which your conversation is only one of dozens of things the person is paying attention to. That is a challenging place for jargon. There's enough distraction and turnover that you'll have to spill a lot of ink. It may well be more efficient to just use natural language, rather than explain jargon repeatedly.
I have to agree with Snarf - jargon is at its best and most useful when it is used among a group of people who all already have the same understanding of that jargon. When in mixed company, use of jargon is best considered not as a tool for the current discussion, but as developing a tool for later discussions.
It does not help that, around here, folks lead with the jargon, and then have to explain it. From an instructional standpoint, that's backwards - you don't want to start by confusing the student, because that makes the student defensive. A better mode of instruction would be to introduce the concept, establish that it is useful, get the student to agree to that utility, and only then apply the name.
Because remember - the jargon isn't actually the important bit. The concepts the jargon stands for are. They should be the focus, and you should be willing to abandon the jargon to get the concepts across, if that's what's needed.