Well, part of the reason you are having trouble understanding it is that you've simplified it all the way down to a trope, which necessarily misses a lot of the nuance of what I sad. I mean, I don't even agree with "don't customize your VIM, what if you have to use vi/vim on a server?", so why would I expect anyone else to?

If I had to distill my point down to a sentence, it would be "be cognizant of your tools and their usage paradigms, and whether large customizations to one paradigm and how it might affect the overall usability, or your perception thereof, of the others."

Yes, it's wordy, but that's simply because not everything is easily reduced to a pithy one-liner, at least not without a large loss of context.