Unfortunately for the me, the reader, I have know way of knowing whether this article is signal (distilled information from an experienced manager) or noise (somebody who isn't good at their job posting opinions because they think blogging builds their online identity).
I'm new to management so I'll be the first to admit that I'm not great at it. I do wish I'd had someone to tell me some of these things when I first started, so you could think of this as advice to my younger self. YMMV.
As for whether asking tough questions makes people feel safe, I'd say, "... maybe?" I can think of hard questions that would certainly make me feel less safe. Two things: 1. Asking the question I lead with got me some great info, so I'm going to continue trying this; 2. I'd want to encourage people on my team to feel able to do the same, so I look at this as leading by example.