It sounds like there’s a combination of things going on there. First, the doctors you’ve seen do sound quite nasty. However, the whole “I don’t believe age affects health or fertility, my anecdotal evidence counteracts your decades long medical degree” vibe I get from this article is kind of weird.
They know more about the science than you. They know more about the statistics than you. They studied medicine for 10–15 years, and so they’re not just talking out of their ass when they tell you that *on average* people DO need to get checked more for cancers or other diseases once they reach 40. I got told that when I was around 40 my eyesight would start to decline *when I was 18*. Because that’s apparently something that happens to most people around then!
While you may indeed be in the peak of health, the job of the doctor is 1. heal your ailments and 2. PREVENT future ailments if possible. My dad is a GP and he sees thousands of people in their 50s and 60s with cancers, degenerative diseases etc, that could have been prevented if they’d been tested in their 40s. So they’re clearly just wanting to be safe and give you your best chance at a healthy future. They didn’t say it a nice way, sure. But that doesn’t mean what they said was invalid. And the fact that multiple doctors over many years told you the same thing, doesn’t mean there is “ageism” affecting them, it means that you maybe should listen to the experts. Because even people who feel healthy and in the peak of their lives can be in the early stages of some kind of cancer.
Imagine how horrible it must be for a doctor to have to tell someone “I’m sorry, you have stage 4 bowel cancer” or “you have stage 3 breast cancer”, knowing that if they could have caught the disease earlier they would have been able to save the person?
Doctors WANT to save lives. That’s their whole deal. Each death that happens, if preventable, weighs on them. So, maybe try being empathetic to why they care about things like statistics, risk levels etc. It might be annoying but it’s better than the alternative.