People can't be blamed for failing to read the full text of the proposition. For one thing, a recurring tactic in the California ballot initiative system is for opponents of one proposition to push their own proposition, with wording that is difficult for a lay person to distinguish from the other proposition, but with some clause that causes it to override the other proposition and nullify its intended effects. What typically happens is that voters will see two propositions that seem to have the same laudable purpose, and will vote for both of them; the deceptive proposition passes as well as the genuine proposition, and nullifies the genuine proposition.
I remember on one occasion in the 1990s, when there was a suite of propositions sponsored by environmental groups, and an opposing suite of propositions sponsored by industry groups. I felt that, as a good activist, I really ought to read through the propositions themselves. For one thing, I'm not a lawyer, and it's a rare person who enjoys spending an entire day reading through dense legalese. More importantly, however, even having done that, I still couldn't tell which proposition was which, except by checking what political groups supported which proposition.
In this case, it was more a matter of pushing a proposition that sounded good from the ballot summary. If someone had a proposition for providing free milk to orphans, it would pass, without most people noticing that on page 35 of the text of the proposition, it called for the purchase of milk contaminated with depleted uranium.
Most people headed to the polls, I expect, with a firm decision about which candidate for president they would support, but little idea of any other issues that would see on the ballot. This is a problem with how our elections work: I doubt any media outlet spent five seconds discussing who was running for the community college board, but that sort of local issue is one in which an individual vote is much more meaningful than a vote for president.