Why are tempo runs not important for racing 10k?
Because malmo is a crotchety old man who wishes things were like "the good old days" when nobody knew about the anaerobic or aerobic threshold and everybody from 800 runners to marathoners did mile repeats every Monday and hard 400s every Wednesday.
Meanwhile in the 21st century, the runners who are actually racing, PRing, and smashing the old records from the '70s are doing long runs, threshold workouts, and tempo runs as their bread-and-butter.
From my experience tempo runs are one of the most important things. Its interesting because at my school the coach keeps the training relatively similar from indoor to outdoor and the 10k guys end up tanking HARD. Same training from 3k steeple to 10k with the main workouts being 800s, 1200s, and 1600s. He completely throws away the tempo and it shows in race performance even though he thinks its all a mental game.
If you do nothing but interval work on the track you will just become fatigued.