One of the things bike manufacturers seem to think is a good thing is interlocked front and rear brakes. Personally, I think they are dangerous and deadly on anything but paved roads or in serious poor traction conditions.
It's like so many refused to make convertibles with either front-wheel drive or AWD assuming NOBODY would drive a convertible in snow. I grew up driving my mom's '67 LeMans rag-top equipped with studded tires and sandbags in the trunk in snow but studded tires are ancient history.
But without interlocked brakes you can go slow and depend on the rear brake without sliding the front end. One of the reasons I'm not trading in my 2004!
Personally, I believe your understanding of the FJR's brakes is flawed. You have to pass a pressure threshold before the front engages. Using the rear brake to do whatever you're going to do won't magically crash you.
All this dirt road amazement makes me laugh. I grew up on a dirt road, and o still have to ride it to get to my mom's. Had to ride a steep dirt road to get to my brother's for almost 11 years. It's not that hard.