> I still don't see the problem. Apple can say this app wasn't verified for safety by Apple because...it wasn't.

In the context of this popup, Apple is not just the manufacturer of the device, it is the operator of a competing marketplace. The fact that they suddenly present themselves and state that they did NOT verify this app implies that the quality of the products offered in that market are somewhat inferior to what Apple themselves are offering. <-- This is anti-competitive behavior

> It's only weird because it's so obvious nobody would think otherwise for a mall.

No, it's weird because Walmart has no business telling customers of OTHER markets that THEY don't vouch for its quality.

In this Metaphor Walmart was already caught and ordered to stop hindering other players from competing on equal grounds, so naturally Walmart cannot put someone in front of every competing store to cast doubt on their offering.