Well yes, of course LL allows it. Nobody disputes that. The discussion is of the "you can, but SHOULD you?" ilk. What kind of culture do we want?
LL has chosen to allow this because if it doesn't, you don't have absolute control over your own land. I can see why the system doesn't create land contracts that state the owner must agree to anyone wandering into their parcel for a minimum of x seconds at any time. I get that and I understand why it works that way.
The "law" may need to be set up in such a way that it doesn't force you to host randoms. But that doesn't mean we shouldn't also work towards a culture that allows some leeway to account for genuine errors and a passable, explorable world.
I suppose I could set up a system in my RL driveway that throws animatronic tarantulas or Sharpie ink over anyone who sets foot in it, without any warning at all. It's my land, after all. Will it deter burglars? Probably. But it'll also get the postman, the meter reader, the innocent person who accidentally walked into the wrong driveway and didn't realise until they got close enough to see the door number, the breakaway toddler and their parents, you get the gist. Can I legally do this? Probably.* Should I? Not so sure. Is anyone being entitled by having a discussion about it and suggesting alternatives? I don't think so.
I like the ideas of a passable air passage at a certain height that wouldn't impose upon homeowners, and rebuilding the tighter public passages so that it's easier to navigate through them without impinging on someone's land. I also like the idea of a landowning culture that gives a reasonable warning to people who trespass and then, if they don't skedaddle, simply sends them to the nearest available public space. If all you want is to protect your land, what more do you need?
I can't recall offhand details of insults in this exchange, but even if there have been some, I think most posters have been quite reasonable in expressing their thoughts on this matter. Certainly I don't think there's been an avalanche of abuse towards zero-second-TP-homers to the point where all arguments for alternatives become null and void.
*If you know I legally couldn't in your country, ok ok. It's a thought experiment. You know what I'm trying to say.