Well, some people are competitive about distance and some people are competitive about speed. Also there are theories about slow-twitch and fast-twitch muscle fibers that lead some people to do better with endurance sports and some to do better with sprinting, so there may be a natural bias involved.

However, as an ex-competitive swimmer who specialized in the sprint events, going fast is just fun, and training so you can go faster increases the fun. This can be a little dangerous on a bicycle however, caution is advised, especially as one grows older and injuries take longer to heal.