Consumer operating systems started detecting captive portals long ago, and at a time when HTTPS was much less common than it is today for casual usage. Post-Snowden, there has really been a multi-industry push to use HTTPS everywhere even for "boring" use cases where a naive person wouldn't assume snooping to have much consequence. But captive portal detection appeared from Microsoft, Apple, Google, etc. years before that push.

HTTPS absolutely should reject a captive portal trying to hijack it, that is the point of it.

But "work around HTTPS" remains a weird way to describe this. The captive portal is the culprit in need of a workaround, not https which is doing what it's supposed to be.