.Net 4.7.2 app does not honor SCHANNEL protocol settings

Question

I disabled TLS 1.0 and 1.1 like so:

[HKEY_LOCAL_MACHINE\SYSTEM...\SCHANNEL\Protocols\TLS 1.0\Client]
"DisabledByDefault"=dword:00000001
"Enabled"=dword:00000000

[HKEY_LOCAL_MACHINE\SYSTEM...\SCHANNEL\Protocols\TLS 1.0\Server]
"DisabledByDefault"=dword:00000001
"Enabled"=dword:00000000

[repeat for 1.1]

When I hit https://clienttest.ssllabs.com:8443/ssltest/viewMyClient.html with a browser, I get

TLS 1.3 No
TLS 1.2 Yes
TLS 1.1 No
TLS 1.0 No

When I hit the same endpoint from the same server with a .Net 4.7.2 console app that executes these lines

HttpClient c = new HttpClient();
var response = 
  c.GetAsync("https://clienttest.ssllabs.com:8443/ssltest/viewMyClient.html").Result;

I get

TLS 1.3 No
TLS 1.2 Yes*
TLS 1.1 Yes*
TLS 1.0 Yes*

Why is that and how can I restrict (or enable) protocols from outside the app? The underlying issue is actually that I cannot get .Net clients on this server to use TLS 1.2 on outbound connections even though it is enabled at the OS level, and understanding why I cannot disable other protocols might help me figure this out.

Answer 1

Ah, never mind, I missed the (*) footnote:

(*) Without JavaScript, this test reliably detects only the highest supported protocol.