Sitting in an airport lounge you shouldn't have access to isn't stealing. Piracy isn't stealing. Using ad blockers on a site that supports itself through ads isn't stealing.
Theft is wrong for well-known reasons. Most of those same reasons apply to these situations.
What do you think of random people occupying your house while you are gone out to work or grocery store? Is that okay too?
> Using ad blockers on a site that supports itself through ads isn't stealing.
I agree with this because browsers are "user agents" not "website agents".
If curious, consult a qualified legal representative in the appropriate jurisdiction.
So opposing trespass is now rooting for corporations?
1. Getting into an area you don't have access to: Trespassing.
2. Tricking the security they have in place: Fraud.
3. Taking snacks from the lounge-area: Stealing.
You are consuming a resource that's finite. You are literally taking value from the provider without asking or paying for it. What do you propose we call this?