Well.... since the Catalyst was willing to let Shepard use the Crucible to destroy the Reapers.... why does he even bother fighting Shepard when Shepard decides that he will take the Reapers out conventionally?
So be it? It's the SAME THING AS THE DESTROY OPTION! They just created the biggest plot hole in the Universe.
Ugh, no. It doesn't work that way. Shepard refuses to do anything and the Reapers wipe everyone out. The next cycle prepares because of what Liara did. They have MORE than enough tech to defeat Harbinger the next time he's around.
Starbrat tells you to pick a color since his stupid idea doesn't work anymore. Since you won't pick a color he has no better ideas still so he just goes back to Reaping.