I have friends I've had in my life for decades people who I truly loved and admired but as soon as they become friends with people who I consider of poor character, I become disappointed at that friend and begin to question our friendship. And rather than be honest I start sabotaging.
Oh dear, that is very harsh. Why do you have such high standards for your friends?
I think it is lazy not to want to have standards for your friends.
It is normal to expect friends to have the similar things in common but it is not good to expect them to meet some high standards. Sabotaging all your friendships will leave you without friends.
It's to weed out the weaker links for us people who are better friends.
I thought that you truly loved these people?  Perhaps you can speak to them and let them know how you feel, because intentional sabotage of a friendship is both wrong and very hurtful for your friends.