Operating speed of BJT and MOSFET
The reason they are not answering your question is likely because I was able to type "why is a bjt faster than a mosfet" into Google and get this as the very first search result:


  "Therefore BJTs are more suitable than MOSFETs for driving low-power LEDs and similar devices from Micro Controllers Unit (e.g. Arduino). BJT can switch faster than MOSFET due to the less capacitance at the control pin. However MOSFET is more tolerant to heat (stable to thermal changes) and can simulate a good resistor."


So, to answer your question, a "BJT can switch faster than MOSFET due to [there being] less capacitance at the control pin."