Who is supposed to issue this apology?

The person writing the press release for such an apology didn't do anything, so there's nothing for them to apologize for. The people responsible for Microsoft's anti-OSS stance are minimally involved in 2018, if at all.

There are plenty of people and companies who apologize without putting action behind it. Apologies are a nice gesture on a personal level, but they don't mean anything without action, and they don't mean anything at all at a company level. Microsoft is, at a minimum, showing it wants people to think it's changed. People unwilling to give them a chance are not going to be persuaded by a press release with apology in the title.