Oh i got your meaning now, I've tested in my locally, even i set this sorting to order by title `Categories Listing Ordering`, that child categories doesn't respect this, we will fix this in next release version.
For now, i did applied some fix into your site JoomlaFolder/administrator/components/com_easyblog/models/categories.php, it should respect the alphabetical sorting if you choose this `Categories Listing Ordering` setting to 'Order by Title'.
I also realised you did arranged your child categories from your site backend.
If next time you added new categories for this, you do not need to manually set the ordering from backend, you can just choose this ordering from backend, you can refer on my attached screenshot below.