What is your point? Sitepoint didn’t create the forum software so why are you holding that over them? You did create your site, you are responsible for your direct action/in-action.
Also, the forum scales to mobile/tablets just fine and is very readable without zoom.
Lastly you actually can scale your font by altering the text scaling in the browser settings on mobile.
Default:
Scaled: (note how the UI didn’t break)
