Some “militant” urban cycling commuters do things like attach a pool noodle horizontally and vertically to create space and visibility. I’d probably hazard a guess that avoiding highway miles also lowers your risk profile substantially.
Freeway driving tends to be the safest driving, in any vehicle. This is because speed deltas are typically low, and there are no cross-streets or stopping.
I think the confusion may be that you commented on freeway safety, whereas the comment you replied to discussed highway safety. Freeways are limited access highways; not all highways are freeways.
'Freeway' is a regional term, but the Federal Highway Administration describes them as limited-access with directions of travel separated by a barrier.
Yes and I believe when OP said highway they meant it colloquially, as in a freeway, hence using that term in my reply. A highway wouldn't really make sense since it encompasses just about every road, as you say.
Nobody is cycling on either unless there's dedicated infra anywhere even the slightest bit urban. In rural areas cycling on a limited access road is generally "fine"
Most Americans use freeways, and most do not use motorcycles. It's always hard to compare a rare thing to a common thing, it always has surprising problems. It's like when people on Reddit worry about radon in their basement, but the incidence rate of whatever cancer it was associated with is so low anyway.
What about agency? "Don't worry about kids choking on Legos, kids don't die from choking on Legos" - but that's because parents well informed and really vigilant about it, compared to say batteries. Motor riders avoid freeways.
I'm not sure I understand what you're getting at. There are plenty of statistics available showing that freeway driving is the safest driving vehicles do. There's not as much available for motorcycles specifically, which is why I dug up a relevant link and shared it. It seems to hold true for MCs too (and I have no reason to suspect it wouldn't.)
The fact that people describe someone on a bicycle placing less than a pound of foam sticking out from their bicycle, usually shorter than the legally mandated passing distance, as "militant" when trucks and SUVs are purposefully designed by car companies to look as aggressive and angry as possible, really tells why US vulnerable road user safety is plunging while European vulnerable road user safety is going up.