I have a couple comments to make about it. I think you are quite right to be skeptical about this for the reason that they appear to be trying to redefine all of these different diseases and point them to a common and bizarrely unrelated cause. I will pass the word on to some blogging doctors, but when you see weird buzzwords like "exogenous semiotic entropy" in a low-tier pay-for-play journal, you are likely encountering fringe beliefs about medicine. They are tying too many very different serious diseases to this one chemical, and there would be a simple way to prove this. If one chemical was causing all of these conditions, then you would find that there would be an association between people with alzheimers, autism, diabetes, etc. If someone had one disease they would be more likely to have the others at the same time than someone without the disease. I can find no discussion of this in the paper.
I tried looking up the definition of "exogenous semiotic entropy" And it appears that this paper is the only place where this term appears on the internet, along with uncritical sites promoting it. https://www.google.com/#hl=en&sclient=psy-ab&q=%22exogenous+semiotic+entropy%22&oq=%22exogenous+semiotic+entropy%22&gs_l=hp.3...1370272.1371355.3.1371518.104.22.168.0.0.5.193.1454.0j9.9.0.cappsweb..0.0...1.1.9.psy-ab.v33O3CYsCZs&pbx=1&bav=on.2,or.r_cp.r_qf.&bvm=bv.45512109,d.aWM&fp=438b9e08942244a7&biw=1180&bih=672
Semiotics has to do with the study of language, and entropy is a measure of disorder in matter, so what are they defining pesticide exposure as a disorganization of language that comes from outside an organism? Sounds like pseudoscientific garbage to me. This is undefined in the paper - yet it appears in the abstract. Beware of bogus buzzwords!
Their information about agriculture doesn't seem to be very good at all. Wheat is not glyphosate-tolerant, so I don't see how that could be a major source of glyphosate exposure. Also, sugar is highly refined and though glyphosate is applied to the beet plants the sugar is very pure. I don't think any glyphosate is even detectable in sugar. I know the DNA and proteins aren't.
Finally, you asked about their credentials, and it doesn't appear that they have any publication history for experiments in this field. The contact author, Stephanie Seneff, appears to have a history publishing novel hypotheses for these various diseases, http://www.ncbi.nlm.nih.gov/pubmed/?term=Stephanie+Seneff but the only actual experimental publication from this author I found on PubMed is a gene prediction experiment involving linguistic algorithms: http://www.ncbi.nlm.nih.gov/pubmed/15693733. This might explain the use of language-related terms in a paper proposing hypotheses about human diseases.
The primary author, Anthony Samsel, can be seen around the internet espousing his views on genetically engineered crops. They appear to be full of inaccuracies, and are rather hyperbolic in nature. Take this one, http://forumhome.org/millions-march-across-the-usa-against-gmos-on-world-food-day-p15126-78.htm where he describes Craig Venter as a Nazi scientist (Poe's Law fail).
Credentials don't make someone right, nor does getting it published in the right journal, but if the evidence was strong for all these diseases coming from glyphosate you would find accomplished doctors and scientists who work with these diseases publishing them in a reputable journal.
In sum, as far as the science goes, this paper appears to propose a set of hypotheses to explain many unrelated diseases with one single cause. That would require an extraordinary amount of evidence. Their discussion incorrectly takes the hypotheses that they propose and leap to the conclusion that glyphosate "may be the most important factor in the development of multiple chronic diseases and conditions that have become prevalent in Westernized Societies." They don't present evidence for this, and indeed only state "maybe", "possibly", and "plausibly" have a role in the many diseases they name, and call for verification of their ideas. Therefore, they only present a mere untested hypothesis, finally ending with the claim that glyphosate "may in fact be the most biologically disruptive chemical in our environment." You don't get to claim that after you say there's no verification of your hypothesis.