You didn’t read it.
Republicans treated Sanders gingerly, hands-off, hoping he would get the nomination because they believed, correctly in my estimation, that he would be easy to defeat; they wanted him to get the nomination.
Had he won the nomination they would have used all the ugly resources at their disposal to vilify and ridicule him, with gross dishonesty, vicious mockery, unfathomable ugliness, and great effectiveness. They’re good at that. Do you deny it?
No polls taken, however many you can find, amount to a hill of beans until they are taken after the machinery of mockery and hate was turned in Sanders’ direction.
I read all the same polls you did. If you didn’t notice the gentleness of Sanders’ treatment by Republicans as they vilified Hillary Clinton then you should have paid more attention to that and asked yourself why.
And don’t call me a liar. I’ve read many supporters perform the arithmetic I mentioned.