The particles in that video are both red and blue — a visual representation of not really their color, but their particle spin state. The particle has both properties at any given time.
In quantum physics, it is a game of probability that we deal with. Does the light travel straight, curve left, or curve right? Quantum physics say it does all 3, but the probability that it will travel straight is the greatest. However, when you block the straight path, you find that it still gets to the point behind the wall, because it curved left or curved right to get around the wall. You can find details on this experiment if you want to follow up on it.by