Exactly, Sanders and his supporters are fine with "playing games" when it comes to party affiliation, downticket support, Bernie super PAC and party loyalty. But they turn and attack Clinton as a shill machine who only exists to serve her corporate masters when it's convenient for them to do so. They have shown that their principles are less important than what will help them at any given time.
People project everything wrong with the system onto their opponent and this isn't something groundbreaking. Hillary could have easily decided not to do a speaking tour after her time as SoS while planning for the nomination. It's a overconfidence on her part thinking no one would attack her on these issues in the primary. Had it been just super PACs the issue would have been far less pronounced. There is also her very questionable remarks regarding why big business was donating so much while also paying her big money to give out pep talks. First she pivoted to 9/11, than she pivoted to capitalism and now she says she is above corruption. What she doesn't realize is that people who hate the current system are projecting a lot of their frustration onto her and her answers haven't soothed that.
So I do question how much it's about these voters being spurred on by Sanders and how much it was just weak messaging and preparation on Clinton's part for this line of questioning. This was still going to be a weakness in a GE if Trump is the nominee and you should be glad that these weaknesses are known now and if Hills is the nominee she has ample time to at least figure out what she needs to change this type narrative so it can't be used by Trump.
In a normal election this would have never been an issue, but this is post recession where much of the recovery isn't making it back into the economy.