It's not possible to login user that does not have access to read children of root when there are Sites created in Site Factory.

Setup:

1. Basic site factory configuration (you can use the one present in behat APP_ENV)
2. "Subtree editor" user, you can create it by running:

export APP_ENV=behat
export APP_DEBUG=1
bin/behat --profile=setup --suite=personas
(clear cache if needed)

Steps to reproduce:

1. Login as admin
2. Go to Site -> Site Factory
3. Create a new Site
4. Logout
5. Login as "SubtreeEditor" (password: Passw0rd-42)

Expected:

I can login without issues

Actual:

Exception:

An exception has been 
thrown during the rendering of a template ("The User does not have the 
'read' 'content' permission with: locationId '64'"). 

64 is the locationId of Folder for created site and user indeed does not have permissions to read it, but that should not stop him from logging in.