The problem is that these idiots are rallied to vote conservative politicians, who then go onto passing laws that are harmful to trans people. You aren't obligated to justify your own existence (and I know first hand how painful and dehumanizing it is to feel pressured into that position), but as a cis ally I'm going to continue defending trans rights in the public discourse.
Laser death rays are probably effective at preventing them from voting, but also may lead to the laser death ray user to not being able to vote either. So probably not worth it.
Due low voter turnout, it should probably be at least 6 just to be safe if you're in the US or UK (95% confidence interval wouldn't include 0 or 1 voter, assuming 60% turnout)