Am I missing something?
Yes, of course. Miles (a length unit) per gallons (a volume unit) should convert into 100 km (a length unit) per Liter (a volume unit). Doing so
33.2 mpg in 100km/L
the input interpretation is: convert 33.2 mpg (miles per galon) to kilometers per liter
and Wolfram|Alpha answers that by
14.11 km/L
or 0.01411 (100 km)/L
The input interpretation given by Wolfram|Alpha is not for Wolfram|Alpha, but for the problem owner.