Free software has only promised its users the Four Freedoms, which are the freedoms to use, share, modify, and share modified copies of the software. That is not an inherent guarantee that it is more secure.

Even if you yourself don't know how to work with code, you can always enlist the community or a trusted friend to exercise freedoms on your behalf. This is like saying right to repair is meaningless because you don't know how to repair your own stuff.