On one hand, this material was naturally present in the earth and it is what causes background radiation. On the other hand, it's been concentrated some and roadways only last so long... then they get milled down, and the millings get reprocessed. This creates dust with health hazards of it's own without the presence of alpha emitters.
On the face of it, seems like a bad idea.
I don't have a very good grasp of the dangers of radiation and tend toward the feeling that radiation is bad and less radiation is good. But I'm also not scared of flying, bananas, granite countertops, red bricks, concrete, smoke detectors, etc. We use zircon sand in ceramics, refractory materials, abrasives, and jewelry which I believe tends to be as much as 10 times more radioactive than raw phosphogypsum.
Then again, roadways see a lot of abuse and deterioration even outside of milling operations, so the risk of creating airborne particulate is almost certain to be far higher than the uses of zircon sand.
All that said, the articles labeling this as "paving the roads with radioactive waste" are absolutely dishonest and manipulative. If they were using granite debris for paving it could equally be called "paving the roads with radioactive waste" (granite radioactivity is in the same order of magnitude), but no one would reasonably consider it so. If you toss out banana peels you might be technically disposing of radioactive waste, but no reasonable person would call it that.
When someone says "radioactive waste" they're trying to conjure images of glowing green goo leaking out of barrels on The Simpsons. The fact that the articles are starting off intentionally manipulating perception makes me doubt the conclusions they are trying to push.