If you resize the browser window the sidebar is the first content that you see. I think the sidebar should be always shown just before the footer, no matter if it is on the right or on the left, as it is made to contain auxiliary content.
For the moment I’m going to move the sidebar to the right, so it falls under the page content. By the way this workaround can not work sometimes.
Thanks for getting in touch! Since we are on a LTR language, elements on the left are stacked first since it is assumed that the person viewing it, reads from left to right. As such, all elements on the left are considered more significant compared to the elements on the right. But I do get where you’re coming from, I just wanted to explain how it was designed that way. Feel free to head over to our User Voice Forums regarding that.
I noticed too that you’re only using the Page Builder’s sidebar and not the one from the theme. You can use Bootstraps push and pull classes to manipulate the desktop view.
The BB Theme offers a Sidebar Template. The settings for which are under Appearance > Customize > Content > Blog Layout. When used, a sidebar will be visible on that page but is fully controlled by the theme(you can place widgets and stuff) but the Page Builder will not have any control to it.