So, there's a group called One sentence startup pitches in Facebook and I posted the following sentence there.
A startup/university/research institution that would prove that the reason why no one has traveled from future to the present is because climate change destroyed the planet before anyone could invent the time machine.
A native speaker corrected me and told me that it should be:
A startup/university/research institution that would prove that the reason why no one has traveled from future to the present is that climate change destroyed the planet before anyone could invent the time machine.
I am sort of naturally skeptical. So I thought I should post here to confirm.