Well, patents are certainly a good way to create monopolies, which wouldn't exist in an actually free market with no patents. In addition, there's interventions in place which don't allow certain tech exports to China, for example. Not sure how much better the situation would be without these.
I think the principle is called perfect market or perfect competition, but it's only a theoretical concept. However, it's certainly possible that the market is less perfect than it could be due to interventions and regulations.
Not endorsing that theory, just offering my best guess at what the person probably meant when they used "Efficient Market Theory" in their comment, based on the context.
You mean a theory that no economic school actually believes? Not even Austrians would sign that.