Can you not see how it's strange to require a rule stating that you won't date drug addicts and psychos? I have a child and I've had long term relationships that included boundaries on how we would interact with other people, I've never felt I've had to state a rule or boundary prohibiting either of us from interacting with people that would cause us harm or has an unhealthy, risky lifestyle that would negatively impact on us. Not because we didn't have anything of value between us to protect, but because the assumption would be that neither of us would consider such a relationship and would terminate any relationship that turned out that way.
The only time a veto rule has ever made sense to me is when I was in a very dark place, plagued with doubt and insecurity about myself and everyone else. At that time, the thought of trusting a partner to make wise decisions about anything of note was laughable, let alone judging who would be a decent person to have a relationship with.