It requires training...
I was once visiting with s South African professor while on a project, and went to his home for dinner. While waiting for the food to cook, he offered up some Marmite and crackers, which, being the adventurous kind of guy that I am, I tried. It was, well, difficult but ultimately doable.
In a toddler seat in the kitchen was his new (1 year old) son, who was just starting on solid foods. My host dipped a bit of Marmite and rubbed it on the child's lips and gums, against head-shaking, arm-flailing protests. But the kid did manage to swallow a few licks.
I asked him what he was about with his son. His reply "This is how we all learned to love Marmite as children".
So another mystery explained.