Sanders is neither the first nor only politician to point this out. And the big problem with Sanders is that he'd rather focus on creating policies whose cost will ultimately be paid for by the middle class despite being an ostensible champion for it. Congress as it is now or will be comprised in the foreseeable future simply will not hammer on the wealthiest Americans as much as Sanders would want in order to pay for his policies. But he's stubborn and radical enough to push those policies through regardless because he's so staunch in cramming his socialist agenda (I'm not using that term like a four letter word, it simply is the accurate label for his platform) down everyone's throats that he'll ultimately have no choice but gradually push those costs onto the middle class. The reason he's able to remain popular and continue to gain ground is because his support base is largely made up of people who have yet to feel the impact of a large tax burden at the level of a middle class living wage.

I'm just beyond the line of living paycheck to paycheck despite making a decent income and I'm not voting for anyone who threatens -- willfully or through blind adherence to an agenda that cannot and will not be implemented in the backs of the rich (who the hell do you think currently and will always pull congressional strings) -- to raise my already ridiculously high taxes, which amounts to about $14k for federal alone, which is before the socialized health care I was already paying for (Medicare) as well as my own as mandated by the ACA. Guys like Sanders are out of control, and they're able to gain popularity by making promises to the people who don't have to pay (yet) for effecting those promises, but see the benefits like they're free manna from heaven, and who cares who pays for it as long as the benefit and they're not the ones paying.