Damage security? They didn't damage the security of the products because of this, if anything you should take of is just how easily these products can be compromised in such manner.
All the NSA did is to steal keys which they can then use to interdict cellular communications, it's not like they put in a weakness by design and then exploited it (which they might have done in other operations but that's a completely different story).
This thing is no different than the digital signatures on the driver used by Stuxnet ("oddly enough" both companies which were compromised were in the same industrial park just a across of a shared parking lot from each other ;)).
Sadly this level of operation is plausible to be committed not only by private intelligence agencies (which we had too many off already) but by crime organizations as well. I've seen case of corporate espionage which were more complex than this one.
Instead of huffing and puffing at the NSA the proper lesson to learn from this is that cellphone carriers should stop relying on SIM card manufacturers in China and India for their encryption.
Heck if the NSA can interdict equipment in transit to tamper with it, how hard would you think does the Chinese intelligence service has to work to go down the street and just demand the keys straight from the source?
It's about a good damn time that people start asking questions on who has access to the private keys which are used in so many day to day operations from the keys used to authenticate your cable modem to the keys in the card reader you swiped your card trough at your local coffee shop. The answer to this should force quite a few people to live in a hunting lodge in Montana for sure.
I in fact would be very surprised to find a single mass used commercial cryptosystem which is actually secure. Because which each and everyone of those the keys to the castle end up being in the hands of the lowest paid employees out there and business practices will always force availability and serviceability over security.