I rewatched the video to make sure, but in terms of specifics, he said that they're experiencing company-wide network issues, which have also hindered their ability to address bugs for the patch (it's cost them about three days of work). Furthermore, the building is being shut down for a yearly maintenance on May 31st and June 1st (saturday and sunday). If they released the patch on that friday, they would have no way of addressing issues if something went wrong that weekend, so they had to push it back to the following week.
Source: The live letter 29:30-31:00 (I understand Japanese)
People really shouldn't think so poorly of the devs when something bad happens that's out of their control.
