I value animals, both common and endangered, but I value my family more. No animal will ever be given safe haven to the detriment of my family. If Sasquatch himself ran out of the forest and started attacking my kid, I'd shoot Sasquatch. No hesitation.
If all my family is available for a warning, "Hey, there's a rattlesnake on the west side of the house", then Mr. Pit Viper would be allowed to leave on his own. But if family members are not able to understand and act on that warning (e.g., young kids), or unable to get that warning in the first place, then I'm sorry Mr. Pit Viper but you are not welcome, despite you being innocent and clueless about any issues you may be causing.
I can't even imagine how I'd feel if I left a venomous snake remain by the side of the house and an innocent child came along and ended up being very painfully sick and losing a leg because of a bite. Of if I tried to move the snake away, but mishandled it and got bit myself. It's not that I fear them, although I do give the venomous ones a wide berth. It's that I don't like the potential danger they pose in populated areas.