Primarily because they generally aren't smart enough to understand them. Here's a list:
1) The settled science on climate change
2) The harm of the income disparity on the poor and middle class
3) The high cost of healthcare services in comparison to other nations
4) Our crumbling infrastructure system (our electrical grid will one day fail and it will be catastrophic)
5) The drain on the economy from corporate welfare
6) Republicans in office not giving a shit about their voters.
1) The settled science on climate change
2) The harm of the income disparity on the poor and middle class
3) The high cost of healthcare services in comparison to other nations
4) Our crumbling infrastructure system (our electrical grid will one day fail and it will be catastrophic)
5) The drain on the economy from corporate welfare
6) Republicans in office not giving a shit about their voters.