Why do people leave their TV on for their pets when they leave the house?

I play 10 hour videos of birds and squirrels for my cat and she seems to like them.

Some people see their pet as family and not just an object, so they feel bad about leaving them while they're at work or wherever. I leave the TV on and have some fairy lights on so she's not in the dark.

They want to let their pets watch TV too.

Because animal watch tv

When I was a boy, the family cat did watch birds on wildlife programmes. She also watched snooker for a while, until she realised that the ball did not appear under the TV when it was potted, as it would do with the home snooker-table. It took her 3 minutes to realise this

To stop them looking at porn on the computer.

so the pet hears the voices on tv and don't feel lonely