Because you label a space as "abandoned" makes trespassing it OK? LOL.
These are not "abandoned" in the sense of a ghost town where all the business and owners are long gone and no longer care what happens to what used to be their property.
The owner, in this case, still exists. The spaces are clearly marked as off limits to guests. They're not abandoned, they're just currently not in use. People are allowed to have property in reserve for future use without it falling under the legal distinction of abandoned, and thus a free-for-all for anyone who wants to go see it.
Labeling unused space as "abandoned" is the height of rationalization. Especially when urbexes know quite well the owner of the property doesn't want them there. It is intellectual dishonesty at the service of selfishness. And *that* is immorality.