That’s the point. There are a thousand different factors that go into the point spread—some big, some small. Yet many would have you think they get done with all of that, look at the spread and then say, “Who we got? Seattle -1? Welp, better make it Seattle -4 then, since they’re at home!”
Home field advantage is just one of the many factors involved that lead them to a number. Yet every time the point spread comes out, you see the fake experts come out of the woodwork doing -3 math to bestow upon us that, well, since Vegas has the Bears -3 at home this game, that means they think they’re even to the Vikings.
It doesn’t. It means that for this game, they believe the Bears are 3 points better. Or, more accurately, -3 is the spread they believe will get the most money on each side.
So enough of the dumbass -3 math every time a point spread comes out. Mack himself probably swings 1-2 points, yet you wouldn’t hear people say on a -1.5 spread , “They think the Bears are evenly matched without Mack,” even though such a claim is just as arbitrary as imaginary neutral field matchups.