Everyone is doing a terrible job of explaining, but they're right.

Gravity, 1G, is described on terms of an acceleration. 9.81m/s2.

What is an acceleration? Is is the rate of change of a velocity. If a velocity changes slowly, it means the acceleration is low. If the velocity changes quickly, the acceleration is high.

Now, imagining a record player. Or cd player. Or your spinning wheel of choice:

You know that points farther away from the center are moving faster in absolute terms compared to points closer to the center.

Because the points farther from the center have a larger velocity, that means after some rotation, the total change of velocity for the outer points must be larger than the change of velocity for inner points. So, points farther away must have greater acceleration.

So, the apparent acceleration changes according to how far things are from the center point. This is why it really isn't the case that it would be 1G everywhere. 1G is a specific acceleration, if if we've established that acceleration isn't constant across the radius, then it can be 1 G only at one spot, not all.