Form not displaying on front page of twenty seventeen
For the TwentySeventeen theme to add content to the Home page we have a few options: 


Set the static front page option in Customizer to a page
We can then have a widgetized front page controlled by the Theme Options in the Customizer


I tested this and  I can add the Page with the CiviCRM shortcode and set it to be the front page.  https://civi47.tadpole.cc/ shows an example of this.

However, if you are trying to set this as the second piece of content via the Theme Options - that does not work for me as well.  I suspect this is due to the way the theme is implementing its home page.