[theorique]

As near as I can tell, complaints about "derailing" translate into "I wanted to make a speech, but the other guy kept insisting on wanting to have a conversation." Is that all there is to it?

Pretty much, yeah. Derailing implies that there exist "rails" on which the conversation needs to go (i.e. the 'agenda' of the person making the speech). If you don't engage his or her central point, then you risk being accused of derailing.

Now, if you really, really don't want to hear what they have to say, that's one thing - you should probably just tell them so rather than passive-aggressively shift the subject of conversation.

But if a shift in the subject of conversation happens naturally, it's not derailing, it's just the natural flow of conversation.

[glenra]

Is there a name for having that sort of agenda? If not, can we call it "railing"?

Does the person with the agenda explicitly SAY "I have this agenda and want to only talk about X and want you to say Y about it", or is the listener expected to magically intuit the intent?

If the listener "really really doesn't want to hear", doesn't that imply they already know what's going to be said, and hence that it's not worth saying it? And doesn't that in turn suggest that shifting the subject is more likely to be informative and productive than staying on the original topic?

I guess I'm having a hard time seeing why railing would be considered LESS rude than derailing. Does railing exist in some sort of additional explanatory context I'm missing, like as part of a roleplaying game or as a form of therapy?

[theorique]

I've never heard it described in those terms. It seems to crop up fairly frequently in areas such as feminism, "social justice", or atheism - topics which are frequently discussed online, which have vocal opponents that repeat certain arguments, and where the opponents tend to use certain rhetorical techniques in arguing.

See, for example, "Derailing for Dummies": http://www.derailingfordummies.com/

As well as a counterargument: https://feministrag.wordpress.com/2012/09/24/derailing-for-d...

"Railing" is necessarily context dependent. Using this particular article as an example, the "agenda" is women's issues in the tech industry in the USA (and, presumably, other developed countries). I suspect it would be interpreted as derailing, for example, to remark that women in the USA are (speaking in a worldwide context) relatively very privileged over many people in the third world, both men and women.

Ultimately, a conversation requires two parties. If someone is speaking over you and doesn't want to hear what you have to say because of their agenda, or their anger, or whatever, that's not a conversation, it's a lecture. They might be speaking on an important topic, or transmitting important information, but no one should pretend it's a dialogue.

If it's twitter, or blogs, or similar, you might as well just withdraw. In fact, you see people do this all the time - back away from conversations when they realize that the other party does not consider it a dialogue but only a means for them to transmit their own 'perfect' opinions to other people.