Its clearly a knee-jerk reaction to unfortunate events. But consider: Farms cannot be reasonably secured. Can't prove 'breaking and entering' when all you have to do is park and walk, maybe cross a fence. So they would need some special rules to make them private space at all.
Since we are on the topic of pure speculation about the intention of this law, let's present another theory: it is in the interest of the farming industry to stop animal rights activists from documenting the illegal practices that are sometimes involved in producing cheap meat since it would be detrimental to their business if they were widely known, and they have been lobbying to get this bill to pass not because of ideological privacy concerns, which are already protected by other means.
From your description, it seems like there is no "breaking and entering" to prove. Trespassing, falsified resumés etc., but there are already laws for that, and the laws themselves don't make it easier or harder to trespass.
Of course you can't prove breaking and entering if that is not what was done. "Can't be secured" means only that they want a large space free from scrutiny without paying to properly secure it.
This is like legislating to make URL modification illegal 'hacking' and justifying it by saying programmers are too expensive.
If our society wants people to have stronger protection for large unsecured areas, they it should apply to all such areas.
No, wrong. Utterly wrong. "Private property" means "not owned by the public", not "hidden from view". Where do you get your ideas on the law? They have no resemblance to reality whatsoever.
Anyone can put under surveillance anything visible from anywhere they're allowed to be. Kids, cats, and cops alike, no permission, no warrants, nothing.