Close, but no. More of, from what I understand from the pamphlet "That was pretty complex for back then, seeing as organisms still have such a structure."
And the sheer depth of confusion that that exhibits makes it hard to answer.
How complex should structures have been back in the Cambrian? Why should a successful structure be removed from living organisms? How?
I can see that the person who wrote your pamphlet is making some collosal mistake, but he's not even specific enough to say what mistake he's making.
It's like trying to punch a fog.
If you will hazard a guess at what point he was trying to prove, I shall explain why he's wrong.
Imagine that you were an expert in physics, and someone came up to you and said "Gold weighs more than it should, and this disproves the theory of gravity", then you'd want to ask him a few questions, like how much should gold weigh, and what the heck he thinks the theory of gravity is, and how it bears on the weight of gold.
I think that a lot of people trying to answer this question have misunderstood it. But this is not to their blame --- what the heck is there in that question that they should have understood?
Edited by Dr Adequate, : No reason given.