Multiple Conditions aren’t working

Since support hadn’t come back with an answer after two weeks of waiting, I searched for “widget logic functions” on the web and found a useful like. I’m providing a link from another site that provided the solution:
https://khromov.wordpress.com/2012/07/17/common-uses-for-widget-logic/

In essence, I had to use the page IDs in an array thus:
!is_page(array(1,5))

Personally, I think using page/post IDs is a bit clumsy.

I still don’t know why the or condition using page slugs didn’t work so I’m keeping this question open because, based on the description/use instructions, it should have worked the way I had previously coded it.