Ok, hold on...

This should clear this up for you...

As was quoted, some of the intake air on a 2-stroke blows right through, which cools the exhaust a little.

BUT!

A bigger reason why 2-strokes don't do as well with smoke is that there is an exhaust stroke on every cycle which blows the oil out of the muffler, on a 4-stroke, the oil gets to sit inside the hot muffler for 1 stroke which gives it MORE TIME IN HEAT, thereby allowing it more time to reach the smoke point.