It's not that hard to rotate your phone into landscape orientation. This is the way you should always take video. Tiktok be damned.
They could be forgiven though if the platform they were streaming on forced it on them. Apparently I'm not trendy, but at least I can still be proper.
In 2018, I stood atop Haleakala and started to FB Live the sunrise. I turned my phone to landscape mode, and FB live stopped and gave me a message that it couldn't operate in landscape.