The problem is how will you keep someone alive long enough to get there. Its not like there’s a Walmart out there to stop and get gas and snacks and oxygen...rebreathing apparatuses won’t do the job for that long of a trip. What if they start out when the planet is primitive but by the time the get there they’ve advanced enough to strip citizens of their rights and become O’bummerland 2. Its not like they can whip that wagon around and head back home. I say we just take care of our own planet, depopulate voluntarily to keep from killing and wasting our own planet and we’ll be fine...: )
you are assuming we know all there is to know about space travel.
I think Bob Lazaar’s description of the alien spacecraft as traveling with a gravity drive that essentially shrinks the distance between space between two places and you hop there in an instance is real (Seriously!)