Well I often have a choice about who I am working with, as do some of my other friends, and we always choose each other first. In part that is because we like each other, and have been working together for decades, and its also because we know and trust the work the other can do.
Brandon Teena is a very strange case. I have no doubt that being trans led to his murder, but I do not think it was the only reason. If it was, I think they would have killed only BT - and might have got away with it. But three people were killed. And where most hate crimes are crimes of passion, the three were executed, which is a whole other level of murder. I've always thought Meth (very big business out in that area), but there was a lot of crime going on with that group (the two killers were already two-time felons, not the best choice of running buddies - and charging them with rape would have been a third strike in a three strikes state, so that was a mandatory life without parole, which of course is part of the problem with the 'get tough on crime 3 strikes stuff, at that point you have almost nothing to lose, which is why most police do not favor them). His troubles really started with the arrest for check forging, (which is not smart in a very small town,) and he was in Fall City to begin with because of legal trouble in Lincoln. So the Hollywood version (shocking) was not the full story. But it also may be that BT just got caught up in what a friend of mine once called "Twin Peaks on the Paririe" because that little section of the country is very, very weird.
As for the standards, and the law like a 'bright line' something they can test and point to, what you are proposing is that everyone is TS if they say they are, in that case, would not all TG people simply claim to be TS? To say she was "highly passable" does that become the standard? Because that would really skewer things, I know lots of people who after HRT and SRS are not achieving that goal.
And, at some point, if your talking about a legal deal, you are talking about evidence. About a standard of proof. About a way to define who is - and who is not - in the class you are trying to protect.
And, under our system of federalism, there are differences between the states, and people do have differing rights from state to state. Trust me, getting caught smoking marijuana is a lot different in SF (where they might tell you to put it out, maybe) and Texas, or South Carolina.