Which means if we get discovered by an alien probe it will look a lot like getting on the wrong end of a nuclear war.

I remember there was a quote from some sci-fi universe that there's "no such thing as an unarmed space ship".

I believe that is the "Kzinti Lesson" from Larry Niven:

"A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive."

https://tvtropes.org/pmwiki/pmwiki.php/Main/WeaponizedExhaus...

If you can get any kind of spaceship up to speeds to reach other stars within reasonable time - you've got an amazing weapon. Just ram into something at full speed. Ok, if you have enough energy to correct course to aim, only.

It’s more than twice(1) as easy to make a rocket-propelled bullet than a rocket-propelled vehicle!

1) It’d be exactly twice as easy but for Tsiolkovsky!