Ok, it's actually right under one false assumption: that we are limited to using our existing text-based tools like text editors, grep and so on. As long as we use these existing tools, this advice is quite valid.
However, we are absolutely not limited to existing tools, we can and should make new ones that augment how we work and allow us to reach more dryness without compromises. You could have tools that let you work with ASTs, that expand code on the fly, show you higher level information, let you debug and step through sections of code effortlessly.
In the end, dryness is good, because it means you have less repetitive work to do when things change (and software is all about changing, unless you don't want to make progress). So it's very well worth investing into being able to achieve dryness more naturally without the downsides.
To quote Bret Victor, stop "blindly manipulating symbols." (You don't have to do do so overnight, just as long as it's a goal you work on achieving as time goes on.)