This article had more of the backstory. Many European and North American companies had already cancelled, and MWC had apparently lobbied the Spanish government to declare a health emergency, which would make insurance claims easier.
Yes, and the HN guidelines do call for posting original sources. However, corporate press releases tend to contain less information than third-party articles that fill in details and give background. I was commenting about this elsewhere today: https://news.ycombinator.com/item?id=22311802.