Look in the lower left corner of the picture. Mesh.
In sticking it in a bin and shutting the door on it, it’s likely the mesh was blocked. That would render the bag almost airtight.
It’s hard to tell what’s lies and what’s journalistic sloppiness, but the picture of the mesh isn’t.
>> The owner zipped it up so that the dog couldnt breathe.<<
And you know this how?