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Fairly simple to answer.
As a whole (to generalize, of course, but the far Left and the far Right are fairly recognizable in their approaches), the Left wants to accomplish what Barack Obama so clearly and repeatedly promised when he ran for President: They want to "change", "fundamentally transform", and "re-make" America, all his words.
It's not unreasonable to ask why someone would want to "change", "fundamentally transform", and "re-make" something that they like, and it's therefore not unreasonable to wonder if these people like this country, let alone love it.
Marxism, socialism, communism? No, that's a mistake the far Right makes when they try to explain what they're seeing happen. A Euro-social democracy? That's more like it. This would require bringing America's dynamic nature down a few pegs, finding a more mediocre level, and we're getting there pretty quickly. I'd guess this will take another 20 years or so, depending on how often the Right continues to shoot itself in the foot.
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