As someone with ADHD, it’s actually excellent advice. The problem isn’t the advice, it’s not sticking to it and developing a habit. Now that I use one regularly it’s great. The trick is finding what works for you. I kept putting calendars and planners near my computer, where I could see them, but once I put it actually on my second monitor which is up all the time, it clicked.
It’s exactly as relevant as anyone else’s, and if you can’t infer that I was offering a personal anecdote you shouldn’t be participating in a public forum.
Also, if you take legitimate advice offered in good faith as flippant and dismissive that’s a you problem. Try phrasing your problems more clearly, if you just say “I have a lot of trouble staying organized and keeping track of time” and get mad when people suggest a planner, your problem isn’t ADHD.