Just because you can find a way to pick the lock and start a car that’s sitting on a public road it doesn’t give you the right to do so. Get your own car and drive the same road all you want, loan it out to neighbors and friends if you want. Feel free to pay for whatever fuel or power source it uses, parking fees and insurance and leave the keys in it with a sign that says free to use. You are not entitled to use someone else’s car without permission because it uses public roads.
The GMRS repeater is owned by an individual. It’s his or hers to do with what they want. The FCC rules and common sense back this up. It doesn’t matter if it’s for their own family, or a family farm, or a radio club, or they just let it sit there unused, it’s not yours.
Sure it’s nice when people make their repeater open for others to use but it’s a permission given not an entitlement.
I find it amazing that this concept is so hard for some people to grasp.