They say "axles and hubs" but don't say what in an axle or hub you can JB weld. I can't imagine what you'd want to JB weld on either one of those... even low-load items like ABS sensors wouldn't be worth the risk IMHO.
Good luck getting anything that resembles a decent adhesive joint on that thing. I would much sooner take it to a welder and have it tacked back together.
If it broke after JB-welding it you'd have chucks of JB weld and whatever reinforcing material you used floating around everywhere in the CV joint. Bad news. A reman'd half-shaft assembly is around $60-70... just do it right. A failure could easily turn into a "call a tow truck" fiasco, if not worse, and will undoubtedly happen at the worst possible time.