Calm down, he’s exactly correct in the answer he gives.
What is the most important part of your *BIKE?
A bike can only be a BIcycle (except if the term is stretched through laziness or for humorous effect).
The bicycle is only one sub species of the cycle.
The bicycle is defined by its second wheel, or, to be precise, by having exactly 2 wheels, unlike a unicycle, tricycle, quadricycle, pentacycle, hexacycle heptacycle, octacycle, nonocycle, decacycle, etc.
The important wheel is the DRIVEN one. Without a driven wheel, the bicycle would not work. Therefore, the front wheel is the optional one. Remove the front wheel, and the BIcycyle becomes a sort of unicycle. Therefore the answer is correct.
Remove the seat, or handlebars, or one pedal, or one brake, and it remains a bicycle. Remove the front wheel and it is no longer a bicycle.
As I say to a fencing opponent after I’ve made an unsuccessful lunge, “You’ve missed my point.”
Unicycling is every bit as meaningful/less as bicycling. A question about components of bicycles becomes meaningless if its answer entails that the bicycle is no longer a bicycle. You might as well ask, which is the loudest musical instrument when it isn’t being played. That doesn’t make music meaningless.