I thought I recognized the language in the quote talking about overreaction by Federal agencies, and, indeed, it is from the 4th edition of Medicine for Mountaineering, by Dr. James Wilkerson.

That was 1992, and his very fine volume is now in a sixth edition. Beginning on page 63 is a very thorough, reasonably objective discussion of treatment systems, and their pros and cons. The 1992 material is absent, but on page 63, at the beginning of his discussion, you will find the following, "In recent years widespread microbial contamination of backcountry water sources in the United States has been recognized. The single cell Cryptosporidium parasite is essentially ubiquitous......"