As long as human beings have freedoms, some will use them in ways that you do not like. An example of this is someone who will aquire an animal and not know beforehand how to keep them.
I am on your side on this, if you think that they shouldnt have them. But they have the right to have them, and people like that will aquire them whether you feel good about it or not. That is a direct consequence of freedom.
Ultimately, this leaves you with a decision to make. How will you treat those who have the animals and know not yet how to care for them? Be careful, for if you scold them they may never come to you again for help, and not only will their animals be worse off but it will prevent others from coming to you with questions.
If you are open, caring, and patient, you open the door for some change. No, not everything may change, and neither is it certain. Just think about the probabilities. If you stay calm and do your best to provide good information you have the best chance to affect a positive change.
Give them time; even the worst ones may one day pleasantly suprise you.