^Because the Milky-way was swarming with reapers/about to be swarming with reapers and it seemed likely that they'd "win" and finish off the council races just like they did the (considerably more advanced) Protheans and every other race before them for millions and millions of years.
Sending off a colony ship into dark space where the reapers *might* not bother following them to Andromeda seems like a reasonable contingency, given the options available.
And incidentally: yeah, depending on your choices and readyness rating in ME3, you can get an ending where Earth is destroyed (or at least, sterilized.)
Sending off a colony ship into dark space where the reapers *might* not bother following them to Andromeda seems like a reasonable contingency, given the options available.
And incidentally: yeah, depending on your choices and readyness rating in ME3, you can get an ending where Earth is destroyed (or at least, sterilized.)