I don't know what you thought posting massive images of self-selecting online polls with mostly questions devoid of nuance and/or framed in poor ways across a variety of mostly populist or niche issues was supposed to show.
If you think the question "Are you in favor of decriminalizing drug use?" would receive a net positive response, I don't really know what to say.
icarus already posted some actual polling on gun control.
Here's one on views of government provision of healthcare.
As for your second part, I'm sure he's an honest and principled man. He's also one that panders. He hasn't had to pander as much in safe liberal Vermont. But trying to rationalise his pandering as anything more than pandering smacks of an inability to accept he is just another political animal and not some transcendent mythical perfect unicorn.
That he is still walking the line on gun control is presumably because if and when he doesn't become the Democratic nominee, he'll need to go back to the Vermont electorate for his Senate seat.