They mean that Rodinal is not a speed enhancing developer and its famous for its sharp rendition of the films grain - at any speed. Having said that, this is just a case of no white pants after labour day. Some people care, some don't.
You mention sheets - I have not done this in LF(having no LF gear) but in MF I have frequently pushed HP5+ to 800 in Rodinal 1+25 and I feel confident that you would have lovely results even after one more stop. I find with the very basic methods I use (regular agitation in daylight tank), I still get decent shadow detail and the grain is by no means obtrusive from 6x6 or 6x7 (so you can extrapolate that to LF). I am holding a Ilford postcard in my hand, from one of the fellow APUG members, and its an example of HP5+ at 3200 in Rodinal 1+25, and it too shows remarkable quality given the speed increase.
Is Rodinal ideal for pushing? Probably not, from a technical stand point. Can it push? Sure. Do people do it? I do, others do - I don't see why not try it out. Besides, I didin't get the idea from your post that you were looking for philosophical views on Rodinal and pushing in general... but you will never avoid those answers when you mention Rodinal - people have strong feelings about it, it seems
Best of luck,
Peter.