Everything's a theory, but there's a difference between the scientific definition of the word and the layman's. He's right that evoloution's a theory, a scientific theroy, that means it's consistent with observable evidence from multiple observers, like the Theory of Relativity. Lots of different things have been observed or correctly predicted with it, such as gravitational lensing, time dilation and Mercury's odd orbit that couldn't be quite pinned down with Newtonian Mechanics, but was dead on using Einstein's equations because it took into account the sun's massive gravity causing Frame Dragging. The sun's deep gravity well actually pulls space/time around with it. Whereas the average guy's definition would be akin to "My theory is Mr. Mustard did it in the Den with the candlestick." That's a hypothesis at best, probably more like an opinion. So yea, it's a theory, just not like he meant. That or he was trolling the idiots.