I'm have doubts this is true. There isn't much to go on that I can see from the Mastadon thread. Lance has only two posts I can see:
One reply there is I think the most important to getting to the truth:
My doctor uses this same system and requires interacting with MyChart even to check-in upon arrival at the doctors office. I hate that too. However, I am successfully able to do this without installing any phone apps. How? I use a web browser for the Mychart website. Checkin function is on the website too. Also on the website is viewing lab results, scheduling appointments, and requesting answers to followup questions to both the doctors and billing staff. Twenty years ago you could do all of this over the phone, but thats not the world we live in anymore.
What I think the real complaint Lance has isn't about a requirement to install apps (which as I've shown likely isn't required). Its this part:
They said they only willing to communicate, schedule, and exchange medical information with patients with their apple/google mobile app moving forward,
Did you ask if you could use a website instead of a smartphone app?
I even offered to show up in person for every communication, and they refused.
Lance, in today's modern world you're not going to get most doctors or the staff able to stop what they're doing all the time just because you want to view the results on your labs or give you a referral. The margins in most of these doctors offices and health care systems are just too small.
I have doubts you're being denied service and it feels like its more likely you want to speak to humans instead of computers. I get that, but that's expensive. Be prepared to pay significantly extra for that.
You might be able to get that kind of service from a boutique doctor's practice, but understand they likely won't work with insurance companies (because thats where lots of healthcare costs come from), and expect to pay a good chunk more for your healthcare for the service.