I do see what you're saying but with all due respect, the alternative is how it was before, very few people feeling able to speak about it. Shaming someone into not being able to speak about genuine struggles leads to higher suicide rates - just look at men who have grown up with the "boys don't cry, don't be a pussy, stop being such a wimp" - now male suicides consistently accounted for approximately three-quarters of all suicides in the UK since the mid-1990s. I'm not saying it needs speaking about all the time, I don't recall saying that, but it needs speaking about. People need to feel able to speak about the fact they're struggling. There needs to be no shame on admitting you're finding things hard and reaching out for help.
If you don't want someone speaking to you about their mental health, or the fact that they're struggling, or suffering from a symptom that they've realised most other people don't have, then stop them and tell them you don't want to hear it. Tell them they can speak to someone else but not you, because you find it annoying and boring. If someone is posting about their mental health online, either to raise awareness or to reach out for help and advice, block them and move on. If you find it annoying/depressing/boring to hear about people talking about their mental health then remove yourself from those people, rather than expecting them to keep it to themselves or bottle it up.
Whether you're saying it about me personally or not, it makes no difference, I understand that not everyone wants to talk about mental health and some people would rather people kept it quiet and didn't bother them with it. That's fine, that's absolutely your right to do so. But I don't think the answer is people speaking less about mental health, the impact is has, reaching out when they're struggling etc so the only real option is for you to tell someone to stop speaking if they mention mental health, or block those who talk about it online. It may be hurtful to the person who felt they could confide in you but you have every right to tell them to stop talking. You have absolutely no obligation to listen to them and they cannot make/force you to.
Like I said, I don't speak about my mental health to anyone other than my close friends and even then it isn't a frequent topic of discussion, mainly because a lot of the beliefs and attitudes shared on this thread. I'd hope that if one of my friends shared a mindset with you, they'd tell me so I could see their stance and adjust my behaviour towards them accordingly.