I do not think so, but anyway, it is definitely not a proof that we are further decoupling ourselves from the US, which is the claim made in the root comment. France has launched rockets from France for decades. Being an ocean away does not make Kourou reliant on the US.
I think the opposite because in this specific case we have the US which has the world's strongest navy, and the strongest navy by far in the Atlantic.
My opinion is that there is an implied reliance on the US "allowing" Europe to ship the rockets to Kourou and launch them there.
If our relations ever completely sour, the US might, for example, take over the shipping vessels going to Kourou, kinda like Europe takes over Russian shadow fleet vessels.
Now all of a sudden Europe has no means of launching rockets, except now it can launch to polar orbits. It might seem a stretch, but there is a non-zero chance that could happen, therefore it is better to have an alternative.
> Being an ocean away does not make Kourou reliant on the US.
No, but it makes it vulnerable to the US.
“Vulnerable to the US” can mean so many things that it practically loses all meaning. Even with a launchpad in continental Europe, they have many ways to interfere with this project, from disrupting the supply chain to carpet bombing the launch site.
A ship crossing the ocean is much more vulnerable than a launch site with sophisticated air defences.
The US can also decide to “free” and “bring democracy” to the French Guiana because the rich oil deposits of its continental shelf won’t free themselves.
The point is that a slow ship crossing the ocean with hard to replace is very vulnerable in transit.