I dunno, honestly think the biggest reason is that this is a Platinum Games title directed by Kamiya. It resonates with the crowd here very strongly, even if sales don't always reflect it. It's obvious Scalebound isn't the most important XB1 game nor is this cancellation a huge mainstream impact.
I mean look at how we reacted to much worse news:
Disney Closes Game Publisher LucasArts, 150 laid off, 1313 and First Assault canceled:
http://www.neogaf.com/forum/showthread.php?t=534168 (24 pages)
Lionhead Studios and Press Play closed. Fable legends cancelled:
http://www.neogaf.com/forum/showthread.php?t=1194651 (75 pages)
These are major studios closing down, hundreds of people losing their jobs. On the other hand, we're on page 170 of Scalebound. It's comparable to The Last Guardian's rumored cancellation way back. Another cult favorite which resonates strongly with the audience here but isn't always reflected in commercial success.