I don't see increased tariffs on Chinese goods as protectionism. There are many countries throughout Asia and South America that can produce these goods, it doesn't have to be America. But the way the elites in China have such a strangle hold over the people needs to stop. The middle class may have grown, but as you pointed out, it should have grown a lot faster.
Well, as I mentioned, the Chinese government supposedly stopped deliberately holding the yuan down a while back (does anyone know if this is still accurate? I don't really keep up with this stuff), and they aren't buying US Treasuries hand-over-fist like they used to, thanks to our own currency problems. Hopefully, this will allow the Chinese people to start rising up...although they've been screwed out of years of domestic growth that may be hard to get back.
I actually don't really see tariffs helping to loosen the Chinese government's hold on their people, unless nobody in the world bought Chinese, and they ended up consuming their own goods for lack of other options. Otherwise, increasing tariffs would just mean they'd take a profit hit and/or cut prices (and therefore wages). In other words, tariffs/sanctions/etc. could make things even harder on the average Chinese person. Honestly, there's very little that international powers - like the US - can do to weaken the Chinese regime...especially if you limit intervention to choices that would not have tremendous blowback or set horrendous precedents for sweeping ill-advised foreign intervention. No matter how much it sucks to see people suffer, real change in China is going to have to come from the Chinese people themselves.
Plus, tariffs would really hurt our own economy (not help, like protectionists believe): There would be a lot fewer goods on the market, and prices would be much higher at a time when people are just making ends meet. Since our producer base is so weak right now, it would take time to recover from that...especially considering we have too much inflation, too many taxes, and too many regulations for an efficient and quickly growing producer market with reasonable entry barriers for competition. However, there would be a silver lining: IF everyone in the world, not just the US, stopped buying Chinese exports, they'd eventually have to stop buying dollars, which would force the government to be fiscally responsible (lol, nevermind, they'd just monetize the debt!

). Finally, we REALLY, REALLY do NOT want to piss China off right now, because they hold enough of our debt to turn us into a third world country overnight (slight hyperbole). I know what it feels like to be American, because I've lived here my whole life: We feel strong, we feel invulnerable, and we feel like we can always call the shots and pressure other countries into conforming to our expectations (regardless of whether we should). The truth is, we're playing with a pretty low hand right now, aside from our military might and nukes.
There are other issues too, but those are the big ones (aside from the NAP...and even if you're not big on absolute moral principles, I've frankly concluded that tolerating government coercion in limited circumstances for the supposed "greater good" pretty much always comes back to bite us in the ass, usually because it gives the government footing for greater and greater violations).