Nintendo announced that Blizzard cancelled the Overwatch launch event that was meant for Nintendo Switch, just under two days ahead of launch. It appears they were afraid of people potentially protesting their recent censoring policies.
Nintendo initially announced an Overwatch launch event for Switch would happen on 16 October 2019. The announcement was made on 8 October 2019, which means there was exactly one week between the announcement and cancellation, which is a point that will be integral for a later part of this article.
The cancellation announcement strictly noted that it was Blizzard who cancelled the event, not Nintendo, even though it was supposed to happen in the latter's New York City HQ. Furthermore, fans were supposed to meet voice actors that played various Overwatch heroes and villains but all of that has been scratched.
With all the previously mentioned things in mind, it is obvious that preparation time for such an event had to span a few weeks, if not months and it has been cancelled just like that.
Considering Blizzard don't have anything dramatic happening at the moment, except for the Hong Kong censoring fiasco, it is quite obvious what the reason for cancellation is. There are already plans for groups of fans who are already planning to go to BlizzCon dressed as Winnie the Pooh and Mei, the Overwatch hero that recently became a symbol of Hong Kong protests.
The weird part is that no one announced such protests would take place during Overwatch's Switch launch event but they still cancelled it. Now it only remains to be seen what Blizzard will do about BlizzCon, which was roughly two weeks away from the time of writing.
Nintendo don't seem to be happy with Blizzard's decision, as they didn't stray away from throwing the latter under the bus. If Blizzard do turn to censoring their own event in two weeks, it will be obvious that Nintendo rightfully acted the way they did on Twitter.