They're half joshing with you, Stundent 123. But it's understandable.
Larding is such a basic culinary term than even your regular dictionary can tell you what it is. This tells them that #1. you've made no real effort to discover what the word means, and #2. as professional chefs they see no reason to waste time on answering because of #1.
The point is, while you may be a student, it doesn't seem that you're very serious about it.