Her style works for you, good for you. I admit I’m sometimes also guilty of checking work stuff when I shouldn’t be. The problem is that it does not work for everyone and some people want clear boundaries and separation, and her saying this is in a way telling her people what they should be doing:

That’s why it’s up to leaders to set the tone for boundaries in the office and what good work-life integration may look like

Just because you don’t have a problem with it, doesn’t mean everyone else doesn’t either. If she was an ordinary cog in the wheel like you and me, people might not give a shit if that’s how she prefers to work. But she dictates policy with her position and influence.