The game isn't forcing you to use a controller you entitled prick, just don't play it. I play a lot of this kind of games WITHOUT mouse and keyboard and had lots of fun with them (this isn't even and argument, dumbass, just personal preference).
Also, you want to bitch about the lack of mouse and keyboard, go to the Steam site, buy the game and leave a bad review about the lack of mouse and keyboard support.
"the developer isn't getting a single bit of support of any kind from me." Said the hypocrite.

this dev really dont know that the precision using a keyboard + mouse its a lot better than using a controller with bullet hell games