The difference it makes is minimal at best. Doesn't mean we can't or shouldn't tryor darndest, but we really need to be realistic. Reality is: Most people do not care. It's sick, it's terrible, and it's shameful, but most people just don't give a crap. We, the cat lovers who spend thousands on our pets and lavish them with affection, are the exception rather than the rule. Some people will pay attention and be appalled, but more often than not, the most we'll get is a shrug of a shoulder and our words promptly forgotten.
I do understand most of the people here are the exception, not the norm at least from what I have seen. But it does make me so happy to see how well the cats here are loved and taken care of. There are so many out there that need good homes, it is heartbreaking.
Another thing, so many people "just aren't cat people" either or are "allergic" and just dismiss cats all together. An individual in my old rural neighborhood used to shoot cats, he didn't "like" them walking on his clean cars and using his veggie garden as a litterbox. My cat is inside only, all my cats will be since I learned about that event.
I know I am so called preaching to the choir I suppose on a cat forum, but maybe not. Maybe there is someone out there reading this not knowing much about cats wondering this exact same question.
And the justonelitter people are BYB's. And they have the potential to make hundreds of babies off just that one litter- if they don't spay/n the oops/or my cat is so smart/pretty she needs to have a litter - kittens they produce and also the parents.
But it just hurts my heart so much to not at least try and make a difference and educate. If it wasn't for forums like this one many people would not even know the term BYB. Just the fact this poster is doing their homework makes me happy!