I'm not sure, but think one of the conditions for getting a patent is exercising due dilligence in not disclosing the idea before being granted the patent.. I know it can work the other way around (disclosing) to prevent someone else from getting a patent on the same idea.

e.g. on ideas that are patentable, but maybe not worth the cost to patent, you can use the disclosure option to prevent anyone else from patenting it, by publishing your idea in the public domain. This action puts in idea in the "public domain" where no one can claim rights.

Edit update: -------------------
Found this.... check out hypothetical case #3..

Maybe your attorney is concerned that public disclosure of the idea constitutes abandonment of the idea...