If 'fences don't work' why did Obama put them around the National WWII Memorial?

Last night on the O'Reilly Factor, Charles Krauthammer noted that liberals always claim "fences won't work" in terms of securing the border. Krauthammer wondered why, if that's the case, is there a perfectly functional fence surrounding the White House.

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Alright, here's what I've been on for years. You start with a fence. It's very simple. People say, 'Oh, fences don't work. You make a ladder.' Well, then you build two fences, triple strand fences. San Diego did that in the mid 90's and within a decade, the illegal immigration rate at that point was reduced by 90% and people ended up going through other places like Arizona. If fences don't work, why is there one around the White House? If they don't work, why is it that the Israeli fence which separate Israel from the West Bank has cut down terror attacks within Israel by 99%. Fences work.

It's a fair point, though most would concede that the White House is a special circumstance do to the nature of its chief occupant. A better question would be this: Why, if the Obama administration thinks fences don't work, did they put them around the WWII Memorial to keep veterans out? Why were they palced at the entrances of various national parks? Heck, even roadside lookouts were fenced-off to prevent tourists from gazing upon Mount Rushmore. Eventually, we learned that the order to erect the barricades came directly from the White House.

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Yes, a group of vets did push aside Obama's fence but, keep in mind, they were temporary barricades held together with nothing stronger than bailing twine. ...And the veterans were aided by a host of conservative men and women from Congress. ...And the whole thing had become a painful embarrassment for the administration, so there was no real effort to push back. None of that would be the case with a permanent border fence. So, the question for the Obama administration is this: Your petty goal during the sequester was to keep American heroes from entering a memorial erected to their service. You certainly seemed to think that a series of guarded fences was the best way to keep them out, since your first instinct was to erect a barricade to deny them entry. When vets pushed your barricades aside, we know you still thought the plan would work because you replaced them the next morning. ...Yet, for some reason, you continue to tell us that a stronger, hardened, more permanent fence would do nothing to keep people from illegally entering our country? Apparently, President Obama and his far left allies think fences are the perfect tools with which to punish American citizens. They just don’t believe they can be used to defend them.

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