Hendrik, I don't know why you waste your time with these people. Most of them have no idea about the internals and that is because they have no reference when it comes to genuine kung fu concepts and practices.
To make matters worse most of these guys don't even practice Wing Chun. What they practice is an
incomplete hibreed version of Wing Chun that includes some external aspects but NO internal ones.
At the beginning they believe just learning quickly and incompletely will make them great fighters in a short time. Then they realize that what they are learning is not effective which then results in them cross training in Bjj, kickboxing and so on.
Sometimes when one has two eyes he will still find it difficult to explain things to the blind who have never seen them and have no reference.