That's ridiculous. Access to buildings has nothing to do with socialism. You couldn't walk into the KGB building in communist Russia either, yet nobody would doubt for a second to call it communism. You probably can't walk into Maduro's banana republic palace right now.
In addition, their assets come both from the private industry AND government. Los Alamos is not a private sector business, it's a government owned and funded lab. The first ever nukes were produced in it's entirety there. And you can ask Hiroshima and Nagasaki what that product looked like. Coming to more recent days, the NSA is well known for producing exploits (that were leaked a while back) to access adversary systems, in-house. That they don't sell them or distribute them, doesn't make it any less of a product.
That the government opts to subcontract a lot of the production doesn't turn all the system upside down into, suddenly, a capitalist system. A lot of the R&D some of these companies obtain to build those products were actually funded by the taxpayers (and, I did admit that there's a capitalist component in those transactions).
Let's see a basic definition of socialism:
A political and economic theory of social organization that advocates that the means of production, distribution, and exchange should be owned or regulated by the community as a whole.
The military is outright owned and regulated by our representatives, thus by extension, the community. They might not take direct orders from the general public, but they sure as heck take orders from the representatives the general public put in place, AND get paid from the general public's taxed monies.
Communism is the system that can't divorce the political from the economic side, that's not the case with socialism. That's why there's Social-Democracies all around the world, where social programs live next to capitalism and a democratic political system.
And lastly, if your contention holds true, then Medicare, Medicaid, Foodstamps, none of those are socialism either. They don't control the means of production. They don't distribute any good, or have a product. Under that premise, Medicare for all is not socialism?