I thought I identified the source of the problem!
When I save a document as a PDF from MS Word 2013, I can highlight the text. However, when I save a document as a PDF as a print option from Gmail or a Chrome or IE browser, I get these large swipes of stuff instead of highlighted text.
In a moment, I will post a good example from MS Word 2013 and a failed example from Gmail.
I should add that for years I have been able to highlight and copy text from PDF files produced by the same method above including as recently as before my clean install of Windows 7 Pro and re-installation of Acrobat XI.
Again, I am in dire need of ridding myself of my workaround albatross.
I solved the problem!
The phenomena I was experiencing was the result of PRINT TO THE ADOBE PDF CONVERTER.
The desired outcome and the outcome I experienced in the past, which is demonstrated by the second image above, resulted from SAVE AS PDF.
Sorry for the unnecessary inconvenience. The only hope that this question assists someone else who makes the same mistake I did.