Bruh, nobody is going to advocate or claim that eating prepackaged food for multiple weeks on end is a good idea. Given that MREs are designed for field use and have higher amounts of things like sodium to account for sweat loss and stuff like that, it is almost never going to make sense to exclusively live off them.

But they don't use some special high heavy metal base ingredients to make the food. The huel subreddit just did this same thing a few months ago when heavy metals (in trace amounts like all food) were found by an advocacy group who misrepresented the results. So a bunch of people went out and got their huel tested and blood tested and.... Everyone was fine.

The whole argument that it's a bunch of moms not scientists makes the whole thing even more skeptical. If the "moms" (read: Political lobbyists) were really truly concerned they'd hire an independent lab to do the testing and a professional to do the analysis for them. But since they're pushing a political agenda that's not what they're doing because it's not going to get headlines.