As someone who spent time in both volunteer groups and activist groups, I can assure you that well intentioned people can easily make things worse, not better. It's why I got out of such groups.
The first method you cite: "Changing the way people think about something" is a common example of this. It's very easy (in fact, I would say it is the norm) that people's beliefs are strengthened the more they feel besieged, and that often happens by others trying to make them think about something differently (or about something they don't want to). Easily 80-90% of such interactions have this outcome, and definitely over 50% even here on HN. I noticed this earlier in life, and it was confirmed when I started studying communications and influence (almost all books will mirror what I have said).
That's not to say you can't change people's minds. You do need to have the skills to do so, and the ability not to make things worse in trying to do so.
It's great if you want to change things, and I don't aim to discourage you. It is, however, your responsibility to be able to gauge how effective you are, and know whether you are causing damage or not. Do it poorly, and you will merely make it harder for those who do have the skills.
Giving money is the safest way to help without doing harm - provided you have the ability to identify which organization to give the money to.
In that sense, I have no problem with folks who tune out. They could make things much worse by trying to help.