If you say that people are under the yoke of a bad thing or person, you mean they are forced to live in a difficult or unhappy state because of that thing or person.

A yoke is a long piece of wood which is tied across the necks of two animals such as oxen, in order to make them walk close together when they are pulling a plough.

If two or more people or things are yoked together, they are forced to be closely linked with each other.