When a metals analysis is made, heavy duty acids are used. To effect solubulization of silica, hydroflouric acid is used, as well as possibly nitric, sulfuric, and hydrochloric acids.
In contrast, I have read that our stomach contains 0.1M HCl(plus enzymes), which aren't terribly efficient where silica is concerned. (My background is in digestion and analysis of samples for metals analysis, among other environmental concerns.) I have MTHFR mutations(deals with processing of heavy metals, among a million other things), and I will follow this discussion with interest. I have noticed NO ill effects from using DE, myself.
I think the concern is unwarranted because the material will pass out mostly undigested.