I don’t see it addressed in the article… Are they legally able to charge for the electricity itself there?

Yes, that is why they are cracking down on places where they are charging for the time period.

The stop-use order was applied one day after Weights and Measures received an email alerting them that the charging stations in a parking garage near the Mall at Columbia were billing users $2.35 per hour. Apparently, it is not allowed to sell EV charging by any other means than by the kWh in Maryland.

Many of these HHC-owned chargers have shared power, meaning multiple vehicles share the available electricity, which can reduce the charging speed. If both ports are in use at a shared-power station, the energy delivered (kWh) per hour can be halved, resulting in a higher cost per kWh.