I've heard it differently, but is a corollary: bad tools make it easy for bad developers to do bad things. Good tools make it easy for bad developers to do good things.
We should all care about bad developers because if they make bad products sooner or later you or I will use one! Bad developers are the ones who store your password credentials and personal information in plain text. We should all care about making it easier to do things the right way because then the right way happens more often.
This is one of those things that are obvious in the specific, but we're talking in abstract terms.
Because I am very often (temporarily at least) a bad developer. I am tired, or sloppy, or unmotivated by a particular project, and I make mistakes. I want my tools to help me.
Most people, in my experience, are both good and bad developers in different measures. Tools that help the bad developer therefore help all developers in those moments when we make mistakes.
> Do not tell me that Facebook and Wikipedia are built in PHP. I’m aware! They could also be written in Brainfuck, but as long as there are smart enough people wrangling the things, they can overcome problems with the platform. For all we know, development time could be halved or doubled if these products were written in some other language; this data point alone means nothing.
Why do you care about bad developers? They won't do good things either way.