Multiple categories – by name

How come category_name' => array('Ins', 'Pub'), doesn’t work, but 'cat' => '7,10', does?

When I try the former, it just lists posts from all the categories!

Full code: https://pastebin.com/uYgP8Tey

It’s on the front-page in an is_frontpage bit. There are two more loops on the page. ‘Rewinding’ or clearing loops did not help.