SumT is not being dramatic.
Genosha is a confirmed part of the movie.
Magneto is in the movie and Kinberg says he always writes meaty roles for J-Law, Fassbender and McAvoy. They're the big stars, the highest paid - and they aren't getting just a cameo for the amount of money they're earning.
So if you think Fassbender's Magneto is going to sit on Genosha doing embroidery, you are sorely mistaken.
Furthermore, Jean Grey has to descend into darkness and be made a real threat. Do you think that will be by spilling hot coffee on someone, lol? In the comics she destroyed a planet of aliens. So it seems perfectly plausible that in this film she destroys Genosha as an equivalent of the comic book scenario.
And do you think Magneto will carry on with his embroidery when that happens?
Seriously, use a bit of common sense.