There is nothing vigilante about this. Home owners have a right to protect their property.
Yes, their own property only.
Vigilante action would be appointing oneself to threaten a malefactor (thief, arsonist, vandal, burglar) anywhere except on one's own property, by a person not authorized particularly by the property owner to do so, nor authorized by the law to apprehend law-breakers for the general good.
Merriam-Webster's online dictionary (click here) says this:
Definition of vigilanteBe warned. You can get yourself in a whole lot of trouble when you decide to physically interfere (not merely warn) with someone else's interpretation of his/her life, liberty, and/or the pursuit of happiness. In the recent Kenosha "protests," Kyle Rittenhouse was clearly engaged in vigilante action. I'm not saying that was bad, but it was outside of the normal duties that we pay sworn officers of the law for to keep the peace. Even if Kyle survives the vicious attack of the state's attorney, he still can be sued in civil court for shooting the miscreants.
: a member of a volunteer committee organized to suppress and punish crime summarily (as when the processes of law are viewed as inadequate)
broadly : a self-appointed doer of justice