I disagree, because it reduces the freedom of choice and variety of tools available for software development, and increases the dependency on bespoke tooling. Using a more sophisticated word processor shouldn’t reduce the readability of the text produced. If anything, IDE features should be helping to increase the readability of the resulting source code, instead of promoting a coding style that decreases it.

This is about decoupling. The same way one should be able to freely pick a VCS and CI/CD system of choice, one should also be free to pick the IDE, or any other system concerned with source code, of choice. Those should remain loosely coupled, and should each be easy to replace. The more requirements you impose on how source code has to be marked up for intelligible display, the more you restrict the choice of tools it can usefully work with, and the more laborious it becomes to create new adequate tools in that field.