I used the trial version of Adobe Acrobat Pro DC and created a pdf and protected the document against conversion and other parameters. I find that the pdf document created was easily converted to a word doc by a free program like [Name of third-party application removed. -Mod.]
What is the fun in buying this product if my intellectual property cannot be protected from being copied
There is a clear message when you apply a security policy that states that third-party applications might not enforce it.
The PDF standard is a public one now (ISO 32000), and anyone can develop an application that implements it, partially or not.
Unfortunately, many people (ab-)use this opportunity and develop tools that make it easier to get around things like a security policy. There's nothing that can be done about it, unless you use some drastic measures like DRM protection, and even then it's probably not 100% secure.
You're paying for an application to create and edit valid and conforming PDF files. Nowhere does it say that there's a guarantee that people won't be able to copy your work. In fact, it says the exact opposite of that.