This is precisely why I don't care very much about accusations that there's big money in politics. Of course there is - there's huge numbers of people and institutions with money, using that money to advocate for the political change they want to see, and an important strategy for doing this involves promulgating information that they think is favorable to their cause. Everyone is doing this all the time.

Nonetheless, an individual citizen still has to support some political cause (even if you are completely politically disinterested, there are multiple factions claiming that your inaction is tantamount to support for their opponents). Whatever information about the world you think is true, or whatever political cause you think is in your interests, someone else can point to a monied interest who supports similar things. There's no way to use the absence of big money as a heuristic for what political causes are good or bad for you to support.