I think the argument of "civil rights violations" is just ridiculous. They are trespassing and he has the right to protect his land.
However, the other reports on this story have been that this guy has been accused in the past of assaulting people he was detaining, and supposedly he is a raging racist. Now, being a racist is not illegal, and of course he can and should protect his land, but kicking a woman while she is on the ground is just ridiculous.
He should have just called the border patrol and let them handle it. I know the BP is understaffed, and I have been all over those dense southern regions of Arizona, and it's a tough area to monitor. BUT..he is actually pretty stupid to be out there trying to detain these people all by himself considering how many VERY dangerous people are crossing over all the time.