I've been trying to stay out of this whole thing this time around, but in defense of the whole medium:
I truly think using the term "chemicals" is completely taken out of context.
Or at least should be taken and thought of in perspective.
Perhaps if we as Americans called baking soda by it's proper name: sodium bicarbonate or even NaHCO3, or perhaps referring to common table salt as sodium chloride or NaCl we wouldn't find such an influx of fear, misunderstanding and blind judgement. We're just so used to the "friendly names" we've been spoon-fed for generations.
Short of a few additives used that are in fact technically "chemical compounds", we're talking about naturally occurring gellifiers that have been processed to make them usable in a practical manner (little different than milling grain into flour, or drying sea water to make salt)
As Looi points out - agar agar is a seaweed-derived gelling agent used all over Asia for many many years.
It should be noted that any and all additives used in "molecular gastronomy" are all natural and safe products.
Whether derived from red algae, irish moss, vegetable cellulose, enzymes and proteins, or through fermentation of bacteria/yeasts, these are all products and methods thought to be universally safe amongst authorities in medicine and food science.
For those who are truly afraid of the "chemical" aspect of these additives, i suggest you look at your products labels and notice how often you find names you don't know, how many gums are added to your food, or alternate names used in lieu of the unfamiliar.
In comparison, bleach, peroxide, hand soap, shampoo, etc. are all loaded with more lab-made, chemically manipulated ingredients than these "chemicals" in food. Yet not one of us is afraid to take a shower and wouldn't hesitate to bust out the soap?
I won't even get into the chemical aspect of hair dying. (of which I have been no stranger to).
I think the European Union really has it figured out, instead of allowing different names for additives it makes use of a system for listing food additives with a standardized "E" number code.
Food Additives in Europe: E Number List.
You'll find a ton of things you've never heard of by there scientific name, yet i wager most of us consume these on a regular basis in our everyday foods we love.
No one allows these items to be used blindly unless they have been proven to be safe.
They used to say smoking and drinking in pregnant women was okay.
Now we know better.
Perhaps one day they/I will be proven wrong.
But if we outlaw and condemn everything we are naive to, the unfamiliar, the unknown...
We as the human race would have missed out on a world of change, advancement, and in the end (for better or worse) convenience.
I do believe the happenings at the Fat Duck are unrelated to food additives, as (believe it or not) Heston Blumenthal uses a lot less additives than a lot of the other "forward thinking" chefs out there.
Ferran Adria at El Bulli, and Wylie Dufresne at WD-50 are both the kings of this and use additives in nearly every application of food in their kitchens, and to my knowledge neither has yet to have a reported food additive related illness.
I should also note than I am very much a firm believer that quality ingredients and proper preparation and techniques are the hallmarks of good food/dining.
The use of hydrocolloids and other food additives is merely an addition to the "toolkit" and repertoire of the modern chef to achieve the results they desire. A chefs food and technique must be already at a high level before the application bears any merit. For the majority of the chefs (with some obvious exclusions) using these techniques/applications, I'd wager that they constitute 1% of the total amount of the end result.