I overgeneralized here. The operative ban seems to be on carrying things--as the transportaion of objects both disturbs the peace and aids commercial interests. An eruv redefines a neighborhood as part of the "home', bans on carrying objects beyond the home are lifted-- enabling the use of wheelchairs, perambulators, and strollers.

And many eruvim do include the homes and offices of gentiles. The Capital Hill eruv seems to have been constructed to allow Jewish lawmakers to atten commitees, vote, etc.