You can’t keep a satellite launch secret. Also you can send a message by announcing such a launch. Especially to so-called “allies” who don’t take the whole being allied thing that seriously, and like blackmailing their supposed allies with denying them assistance.

You can see most satellites with fairly basic telescopes. The launch is also really easy to track, as you need to clear the launch area and so also there are satellite constellations looking for really hot objects above the atmosphere. The main purpose is to detect ICBMs, but they of cause can also track satellite launches.

For a country that’s outwardly neutral? Seems the right call. Other nations agencies are gonna know anyways.