GP's literal words were "stop voting for people willing to take lobbyist money". The lobbyists and big donations / bundlers come from the same class of people - the wealthy. These dollars come attached with policy positions that favor that class both explicitly (in terms of policies that are explicitly favored) and implicitly (policies that will not be given strong support, i.e. various forms of redistribution).

The only way to run a modern political campaign is with lots of cash, so the cash must be procured somehow. Your two options are to level the playing field with public funding of campaigns (unlikely to happen in the wake of Citizen's United) or for a candidate to raise small dollar donations. The Sanders campaign proved that the latter is possible.