[dsp1234]

This response implies that it the reduced available need be malicious, it could be non-intentional as well.

ex:

During an emergency I connect to public wifi because mine is not working. That wifi has a MITM proxy installed by the owner (because they want to server ads over https, it's a developer's wifi and they were testing with something like charles proxy, etc). This page is now unavailable during an emergency. Thus lack of availability without malicious intent.

The general assumption for HSTS is that, in all cases, it's better to be unavailable than have the possibility of compromise. I'm unsure if that's the case for critical services in times of need.