Hi Jo..,
I don't know why GT always opens at that page but I can tell you about a browser feature I use that lets me set any GT page I want for a one-click open.
I have GT pages saved to my Favorites bar for a quick opening of where I want to go in Guitar Tricks; e.g., Forum, Lessons (Favorites), Songs and the GT Blog. I'm using Windows 10 and the Edge browser but I know it works in older Windows and the IE browsers. I'm sure OS has a similar feature.
With the past month's upgrade of Windows 10 one can now also pin a web page to the task bar. Pick some page you want to open at; "Home", Favorites, etc., and simply pin it (or more than one) to the task bar. Click on the ellipses ( ... ) at the top right corner of the Edge browser to get to the "Pin this page to the taskbar" feature. This too will allow you to open your GT with one click.
Good luck.
-- Chet Atkins