How can that be? Cafes are public, they have lots of people. These cafe visitors have homes with fewer people.
Most people share their homes. They have a spouse, kids, parents, siblings, roommates, something.
At a cafe there are more people, and there's less space for you, and there's some noise. You don't have all your stuff just a few portable things.
But strangers are less distracting, because you think of them less, you care what they think or what they're doing less. Strangers exist less in your mind, so you can be more alone around strangers, even if there's more people. How alone you are in your mind, in your attitude, in your psychology, is more important than physically.
Another reason people visit cafes is to get away from their stuff to avoid temptation. They want to force themselves to do something, so they remove some other options. Their choice to do it, and their lifestyle, don't match up very well. Rather than becoming a more harmonious person, they use crude manipulation such as going to a different building which doesn't have their TV.
People also visit cafes during breaks at work when they aren't near their home. Partly this speaks negatively about their work environment, and partly their co-workers have more attention in their mind than the strangers at the cafe.