Secondly, yes, it was likely a deliberate action to cut off the fuel switches, as you say.
You are absolutely right that there’s an epidemic in the airline industry that forces pilots to stay quiet rather than risk their careers if they’re dealing with mental health issues.
In a sibling comment: “shouldn’t they be given alternate career paths?” No. Perpetuating the myth that people with mental health issues are somehow broken beyond repair is mistaken. Current policy lead directly to that one fellow to lock the cockpit door and slam the plane into a hillside. If Air India 171 has any chance of being a mental health issue today, it should be highlighted and explored. You’re exactly right to be doing that, and thank you.
Anyone who disagrees with this should watch https://youtu.be/988j2-4CdgM?si=G39BwNy1zJEeUi2k. It’s a video from a well-respected pilot. The whole point of the video is that aviation forces people to conceal their problems instead of seek treatment, and that this has to change.