Of course if a thread is damaged you would replace it.
It seems it all has to do w/ the thread on a U bolt being rolled, not cut. And then a big story about what happens when rolled threads are reused a 2nd time, compared to cut threads.
No mention of why regular bolts, of which most all are rolled threads, can be reused. It also appears that the only "official" statement to not reuse, come from the mfgs and sellers of U bolts. At the bottom of one such article, and in smaller print, it stated that it was only their suggestion, and that you can do what you want,.......as if we didn't know that.:)