Something to consider and related…
The country currently has upwards of 30 million illegals . If only 10% of them have bad intentions against our country, that leaves a potential army of 3 million people that theoretically could attack us from within our borders.
Even more obvious is the vocal and very visible terrorists organization, like Hamas, oops I mean the People for Palestine, that do hate our country and are definitely trying to disrupt and/or destroy our way of life.
Just to name a couple of possibilities of who is responsible for these events.
They were obviously not intended to breech the gates but to understand our response capabilities and strategies.