"Their resentment may even cause them to push for keeping the icon after it has proven not to be the right thing for your product." Either Kara is more than on

"Their resentment may even cause them to push for keeping the icon after it has proven not to be the right thing for your product." Either Kara is more than one person, or this is a grammatical error. It may be an intentional grammatical error but an error nonetheless.