Forgive me If I'm wrong, but you're looking to simply remove all your bookmarks from showing up in Firefox, you've succeeded in removing them from the bookmarks main folder but now you want them gone from the bookmarks toolbar and the bookmarks menubar?

I'm guessing you want an easy method because there is alot of them and you'd rather not sit there all day clicking right click + delete on each one?

You can type CTRL+SHIFT+B to open the bookmarks library window. Here you can select the Bookmarks Toolbar or whatever category in the left pane and on the right pane you can highlight one or several or even all the bookmarks for the particular category from the left and simply RIGHT CLICK and select DELETE.

Does this help you with your issue?

Daniel.

You want to create an installation of Firefox without the standard Mozilla bookmarks? I found an article from 2013 on Mike Kaply's blog, but I don't know whether it still works:

Starting Firefox With No Default Bookmarks | Mike's Musings

If you give it a spin, please report back on your results.

No, I'm not altering setup installer. Just after installation how to do this customization in some automated way? What I exactly need is clear in the snapshot, please...

Those are the default bookmarks that come with Firefox.

To not have those bookmarks appear upon installation or when a new Profile is created, you would need to build a custom installation as jscher2000 mentioned.