Totally disagree with this. It's a way for executives to telegraph their influence, credentials and thought leadership. Having an active LinkedIn to demonstrate your spheres of influence and publish articles on your areas of expertise is pretty central to executive branding.
https://www.linkedin.com/in/malcolmturnbull/
https://www.linkedin.com/in/lukesayers/
https://www.linkedin.com/in/alanjjoyce/
https://www.linkedin.com/in/lyncobley/
https://www.linkedin.com/in/brianhartzer/
etc etc