It depends on the state, downvoting doesn't change that.
Even read the link you posted.

All states allow drivers to use the left lane (when there is more than one in the same direction) to pass. Most states restrict use of the left lane by slow-moving traffic that is not passing. The table below describes the law in effect in each state.

A few states permit use of the left lane only for passing or turning left. These have "yes" in the "keep right" column. Some states require drivers to move right if they are blocking traffic in the left lane. These have "yield" in the "keep right" column. Most states follow the Uniform Vehicle Code and require drivers to keep right if they are going slower than the normal speed of traffic (regardless of the speed limit; see below). These are listed as "slower". A few states either do not require vehicles to keep right ("no"), or permit vehicles moving at the speed limit to drive in the left lane regardless of traffic conditions ("< SL").

The Uniform Vehicle Code states: Upon all roadways any vehicle proceeding at less than the normal speed of traffic at the time and place and under the conditions then existing shall be driven in the right-hand lane then available for traffic ...

This law refers to the "normal" speed of traffic, not the "legal" speed of traffic. The 60 MPH driver in a 55 MPH zone where everybody else is going 65 MPH must move right. Contrast Alaska's rule, 13 AAC 002.50, allowing vehicles driving at the speed limit to use the left lane, and Colorado rev. stat. 42-4-1103, prohibiting blocking the "normal and reasonable" movement of traffic.