I think this happens because networking is always proposed as a way out of a bad career situation. Someone complains online about lack of opportunities then commenters come along to parrot networking as a solution. It sounds like a task you do for career gain.
I have another theory that this creates a lot of rebound anger at the idea of networking. When I was doing mentoring (external to my company, people I didn't work with) I spent a depressing amount of time convincing young engineers that it was a bad idea to burn bridges as they left a company. Way too many people are enamored with the idea of ghosting their job or telling off their coworkers on the way out the door. It takes some convincing to get them to realize that leaving a bad impression on an entire office of people is the fastest way to poison their potential network. Nobody will want to refer you for future jobs if you're a jerk in your final days.
I have another theory that this creates a lot of rebound anger at the idea of networking. When I was doing mentoring (external to my company, people I didn't work with) I spent a depressing amount of time convincing young engineers that it was a bad idea to burn bridges as they left a company. Way too many people are enamored with the idea of ghosting their job or telling off their coworkers on the way out the door. It takes some convincing to get them to realize that leaving a bad impression on an entire office of people is the fastest way to poison their potential network. Nobody will want to refer you for future jobs if you're a jerk in your final days.