Now you can observe them and only intervene when absolutely necessary, thus giving you time to learn more about the attackers and their methods.
If that story is true (and I personnaly think it has a high probability to be), what would a gov or a large org do? Investigate, confirm they have been compromised but then.... leave the hw in place and data flowing back to the alien mothership? Unlikely.
This issue in this thread is alleged to have taken place in August 2018.
In the intervening time, much could have happened.
Did the journalist and/or their friends and family make money on the massive drop in Supermicro stock?
Is the Trump administration asking to push this information out to earn favor in the trade war?
Are the investigators stumped and using this in an attempt to flush out new leads?
No idea.
If you're attempting to hack me or steal data from me and I know you're trying (specifically as would be the case with this chip if the story holds up) then I'm in a much better position to try to figure out how, or provide misinformation, or try to turn someone in the chain of custody if anything needs to be physically handled. Or at the very least, if it's an espionage or military situation, it makes it easier to know who to kill.
All of that goes out the window if you immediately disclose every threat. Whoever is attacking you will simply use the means you haven't discovered yet and stop using the ones you have.
I believe you covered more in-depth content that could be filed under "buy the government time to investigate/respond appropriately."