A huge strategic weakness is depending on a foreign country (perhaps even worse - one moody individual) for your launches.
Edit: ok, got it now. This is about a European rocket serving European strategic needs, why would I be talking about USA?
It's a huge fucking problem if you're not American. If you don't want to be subject to American law. If you don't want your technology inspected or tampered with by Americans. If you don't want the transaction to be in dollars (extra-territoriality of US law on all dollar transactions). If you don't want to deal with the problem of American citizens and companies subject to FISA, who could face severe repercussions in the US if they don't spy or facilitate spying on their non-American clients.
The US isn't really interested in the secrets of some Malaysian or Brazilian TV satellite.
Once again, compliance with US regulations, including export control, dual-use goods and tax regulations, can be weaponized, and has been in the past.
Maybe the TV satellite manufacturer has also supplied a weather satellite to Brazil that contains technologies covered by export control, bingo. Your satellite and your assets in the USA are frozen until the manufacturer provide all the information needed to decide whether or not it was a spy satellite.
The godamn Mars rover is covered by 14 export control technologies. https://www.bis.doc.gov/index.php/documents/pdfs/1008-satell...
It's a minefield and it was designed to be one. I know of several non-defense companies whose first question on the phone is "are you a US person as defined by FATCA and FISA ?".