No, you have full access. You can go utilize 100% of the functionality of the site. Again, you are misrepresenting what availability is in the CIA triad. It does not mean all feasible ways and means of access are supported. Otherwise you’re arguing that all iOS apps are also insecure because they aren’t available to Android users.
If TLS isn’t sufficient (or available) for you, do the paperwork and mail it in.
I’ve read what you wrote, but you are refusing to acknowledge reality. Availability does not even remotely mean what you are stating. You might reconsider taking infosec 101.
Then there is no service that has any availability and all meaning is stripped from the word.
Indeed, and if TLS isn’t sufficient for you then by all means, use the postal service. Hell, you could even go to your local IRS location.