Because you broke the 'cardinal' rule of things your character should never say.
Here are a few things that your character, ESPECIALLY the protagonist (the good guy or the main character) should never say.
1. Let's go kill some puppies.
Pets are NEVER EVER fair game to kill. EVER. If you want to hurt them so they get better and give that feel good ending, fine. But don't kill them. Times have changed from Old Yeller, Bambi, and the like. Nope. Never kill off a pet.
2. That baby needs to be taught a lesson.
NOPE. See #1 but insert children/babies in for the explanation. Same with old people. The old song, 'Bless the Beasts and the Children' holds true.
3. I'm looking forward to the day the earth blows up.
HUH? What character would ever say that, even in a sci-fi book? Usually, the characters are out to SAVE the earth. So, just no.
4. I'm too timid to even try.
In today's day and age, readers are looking for a kick-butt main character. They may start out a little wimpy, but by the end of the book they should stand up for what's right.
5. I'm ready to offend some ____ (fill in the blank with the latest anti-hate group).
When I wrote 'The Lord is With Me,' I was afraid the entire population of the Middle East would be out to get me. I changed many details from the original, worried I'd offend someone who wasn't Christian. I was talking with another guy on Twitter, who had the same concerns. He'd taken on ISIS in his book, and worried. So no. No offense. Yes, you'll get publicity, but it won't be the type of publicity you want.
Ready to change it up a bit? Take on one of these 'never say' things and have your character think it. See what happens. I can guarantee you won't like the outcome.
Have a great week!