This article mostly doesn't claim that diet sodas inhibit weight loss. In fact the biggest focus of the article is research suggesting that some food additives

This article mostly doesn't claim that diet sodas inhibit weight loss. In fact the biggest focus of the article is research suggesting that some food additives (not necessarily those in diet sodas) have helped the pathogen clostridium difficile to evolve in a way that's more dangerous to people. Even where the article discusses diet sodas, it doesn't specifically say that they inhibit weight loss but that they might cause other kinds of harmful metabolic effects through their effect on the microbiome—and that this mechanism is suggested by research but not yet well-established. It also admits that some of those effects, if they exist, could vary widely between people. That might be one reason that evidence nutrition has seemed so hard to pin down: if many of the effects depend on people's microbiomes, then some studies might be almost impossible to replicate in a different population, or maybe even in a different generation of research subjects. It might be true that some large group of people did very well eating one way, and that a different group did very well eating very differently, even if it seems like the advice that you'd draw from these observations is directly contradictory.