Considering how common it is to deliberately break (not just with a "you log in now" modal, but not loading content, spinning forever, breaking layouts, etc) websites for non-logged-in mobile users, that's exactly how petty in imagine them to be. Twitter and Reddit do it, and Imgur comes and goes so I can't decide if for them it's deliberate or just incompetence.
You can add Instagram and YouTube to the list of websites that are painful to use from a mobile browser
it's no doubt intentional if the site has an app. They can scoop up significantly more data about you from their app
"because it's so comically inept and petty"
This is precisely why I did believe OP. This is Elon Musk we're talking about.