Good question -- the answer is that Earth's atmosphere is clearer than Titan's. From what astronomers/planetary scientists have figured out thus far about Titan, the atmosphere is partially composed of a liquid hydrocarbon, and other stuff like ammonia, "fog". The reason is that the moon is so cold that gases like methane and ethane are near their condensation point. It's not completely opaque, but it's pretty thick.
" Titan's thick cloudy atmosphere is mostly nitrogen, like Earth's, but contains much higher percentages of "smog-like" chemicals such as methane and ethane. The smog may be so thick that it actually rains "gasoline-like" liquids."
I.e., don't light a match!
NOTE: Nit-Picky Engineer Mode ON...
> The reason is that the moon is so cold that gases like methane and ethane are near their condensation point.
Actually... The reason that methane and ethane are near their condensation point is because the moon is so cold.
>I.e., don't light a match!
Light a match all you want. Titan has little to no free oxygen, thus, there'd be no combustion.
That would explain it. It would be like walking into a deep freezer where condensation would be all over the place.