I think they're trying to convey "don't throw stones at glass houses." It sounds like they're trying to make the argument that if you're not practicing what you're preaching then you shouldn't preach. Not saying I agree with the sentiment; but I think that's what they're going for.

The reality is that you can have it both ways. I own an iPhone, I know how to build a computer, I buy software, and I know how to code. There is value in understanding how the things you have work, but that doesn't mean that you can't or shouldn't buy a high quality product just because you can't take it apart.