In the process of creating the new membership site experience, Simpleros current strategy is to totally replace the top menu (that can now be chosen in the theme settings) with the left hand side menu.
This is a big issue for all the sites created as websites, maybe with a few courses, but where the intent is to give visitors a "website" experience, which in my opinion in most cases includes a top menu. Many users have moved their WP, Wix, Squarespace etc. sites to Simplero because of the ease of the (old) pagebuilder and the simplicity of having everything on one platform. They will now be forced to move those pages back out to another vendor to keep the top menu option, I can't see why Simplero would want that.