Mmmkay, let's get offended at everything. Even someone trying to be helpful commenting on someone else's comment on a forum where people discuss topics. Apparently you have everything in life figured out, so no need to consider my advice that was not even directed at you. I shared what I personally found helpful, I would have loved for someone to share that with me 10 years ago.
Who’s offended? The reason
I dropped in is
you literally asked, with a question mark where moral superiority came into your post, which to me seemed obvious - surely you wouldn’t begrudge “someone trying to be helpful commenting on someone else’s comment on a forum where people discuss topics,” that would be too ironic! Nobody actually has to get offended, it’s a weird internet trick, or a FIRE trick, your choice.
What stuck out to other people was that you implicitly assumed these coworkers were illogical in a specific way: bad at understanding cause & effect. Even while calling them “grown adults,” you insinuate they must be cluelessly unaware that sleeping more would make them less tired.
Either because I’m just a glutton for more sneering & spoiling for a fight, orrrrrr, maybe it’s sad to me that you seem to want to help & I believe you about that, but you are for whatever reason presenting like kind of a jerk to a nonzero total of people in the way you talk about this... with the same sincerity as before, in your own words, “I suggest why don’t you try”:
Lead with this bit I bolded in your comment when you talk to people about it, & maybe pause there to see if they ask for more advice. For example: “I used to spend my shift exhausted & had to start going to bed at 10:30 to feel rested. I would have loved for someone to just tell me to do that ten years ago.”
It makes you sound more like a friendly fellow (former) sufferer sharing your experience, instead of the unappointed manager of their off-the-clock productivity.
Maybe it’s just what they need to hear, & you change their life, ten years ahead of what you got! Or maybe not, maybe they have a totally different root problem from what you did. But on the upside, you sidestep calling them clueless to their face or any accidental impression of being a condescending jerk, & leave the door open for them to tell you what’s really going on, so you can discover things you never understood about other grown adults.