No polls are accurate. But they lean one way. You shave a few points for Hillary off, you get a more accurate result. Thus, a poll showing Trump +1 = Trump +3-5
Yeah, there are normally polling errors, but they go both ways. A poll showing R+1 is equally likely to be accurate as to be R+3.5, or D+2.5. There's a reason that a factor called the "margin of error" is normally published along with a poll.
I'd also like to point out that there is basically zero incentive for a polling company to rig data. Besides the fact that polls published by democrat leaning sites are normally conducted by independent polling companies and not the site itself, it's just a terrible idea from a business point of view.
Yeah that's right, pollsters are usually polling companies or private universities. Pretty much the only way they make money is by getting lucrative deals with news sites, and the way they do this is by being really accurate so that their polls are in high demand. Publishing fake numbers only hurts the pollster; If they had any prestige from being accurate in previous elections, all of it instantly vanishes, and if they are a new pollster trying to establish themselves, they become a joke.
Publishing bad numbers so that liberals can have the upper hand in internet debates before the election is honestly against their self interest.
