The polls you are seeing invariably poll the general populace or registered voters instead of likely voters which leads to inaccuracy
Jazzbo ...
Yes, they tend to poll more democrats in general. Democrats are more likely to say they are supporters of Biden than Republicans who say they support Trump.
They keep reporting that there are "hidden" Trump supporters that do not respond to polls.
But I can totally understand that. It is like getting a phone call from a pollster and telling them you are proud of having syphilis. And then you are asked if you "somewhat" support getting syphilis again or "definitely" support it.