Busy people have no time to answer polsters. When you heavily critisize one group of supporters (and the social stigma associated with it), dont be suprised that in private they think differently. Finally, intentionally fabricating wrong poll results can psychologically influence weak minded (due to group think and our desire to comply with social norms). So it is immature to accept polls as a real indicator of what people think (especially in controversial political environment).

In reality, a lot more people have traditional values when it comes to race, LGBT whatever, sexism, spiritual values, opinions on Russia, Israel etc. However in public they may be scared to voice their true opinions.