Perhaps he was overly blunt, but his point (I think) is that the
line of thinking is an oversimplification that will become more nuanced with age and experience.
Of course these are issues worth solving, but revolution only happens when its architects are engaged on a deep level with the systemic underpinnings that support the corruption, nepotism, etc. that plague the overarching system in the first place. Like the fact that campaign finance reform is not something the president can enact. Like the fact that small "d" democratic politics is about more than representatives and senators voting for stuff, but also elected leaders like city treasurers who invest and disburse municipal funds, school boards who approve personnel and curricula changes, and other positions whose influence can make all the difference.
In other words, politics is a "bottom up" process, not the "top down" situation that campaign promises like free public college education and financial regulation intimate.
What is implicit in posts like GetLucky's is a worry that these young people Bernie has successfully energized will be deflated, that the cowboy he's presented himself as who's going to whip all the bad guys into shape will be outgunned and outmaneuvered by a political climate he's not ready to navigate.
He'll be dealing with an obstructionist legislature, a potentially crippled Supreme Court, and a staggering national debt his plans as they currently exist would only accelerate, but if you listen to his stump speech, you'd think the sole obstacle to total panacea is that Bernie alone has the necessary DEX to wield the magic wand.