Their reasons I can't tell you, since I have no contact with their staff whatsoever. However, I should note that there's several controversies surrounding rules that they never gave an official statement on, and those are the big debates. In this case, however, we do appear to have reached consensus by pulling out the exact rule-statements. Note that Baron said that "the essence of my mistake was that I don't believe in firing 2 guns at once, but that's just an interpretation error on my part."
Also, keep in mind people can often misinterpret things. In the recent weeks, I've seen someone argue that Full Body Armor protects against magic when the rules state it doesn't, I've seen someone argue that Long Bursts do not use cumulative recoil but just their own recoil, I've seen a statement that "free" means no nuyen cost AND no essence cost. If on each of these occasions, even when the wording in the books seems very clear, they have to come out and clarify because people refuse to go with the most reasonable interpretation of what's written, then they wouldn't have any time left for development of SR5. If they came out every time there was a disagreement on RAW and RAI, it'd cost a LOT of time.