Why help? *What* you do vs. *Why* you do it.

It is possible to be addicted to "helping people."
But seeing ourselves as "helpers" is an attachment to an identity, or ego-construct to which we ascribe a positive value that we do not feel that we otherwise possess. Thus by helping other people we are also fueling our own egos.
Helping people is what fills the void where self-worth *should* be.
When helping others is the only thing that makes us feel like a good person, we are really feeding an addiction.
We are using people to fill the hole in our own self-worth.

As long as we are in this ego-driven mode (being "helpful" because it's the only thing that makes us feel good), we will attract nothing but those who *need help*, and because the Universe can be very literal, they will always need help. In other words, since we continue to wish to "help", whatever aid we give will never be enough because we are perpetuating the idea that someone *NEEDS* help as opposed to the vision that that person is empowered on their own. You simply cannot help someone to NOT be the underdog, if you yourself are focusing on them as if they are.
By doing this, you are operating from a mind-set of scarcity, so what you will ultimately create is more scarcity.

So do we give up on being helpful?
Absolutely Not.
But what is important is WHY you do it. 
There are people who are so centered that they simply enjoy helping.  They *already* know of their own value and are not trying to make something up. They are helping from a place of compassion instead of a place of need.
I can't help but think that this is one reason there is such a high burn-out rate in social service and human service jobs (I did 10 years and that was enough). Like them, I was focused on fighting this injustice or that injustice and I got what I was focused on-more fighting and more injustice.
It's an interesting paradox that possibly the people most likely to go into this kind of work are the people who are the least likely to do any good and the most likely to burn out. 
( In my own defense I have to say that my career in Human Services took place 20 years ago before I changed my thinking)  But it is important to understand what your state of being is when you do. 

If you are *inspired* to help, it is a signal that you are within the Universal flow and whatever aid you do give will generate positive results.
If you feel *obligated* to help, chances are that this will not feel good to you, and that is an indication that your efforts will *not* generate anything but more effort.
Focusing on the problem, brings more of it.
Focusing on the fight brings more powerlessness.

Some people give energy by helping, and some take it away by doing the same thing. The difference is how balanced they are as people in their own right.
So be honest with yourself, and help people as long as it does not detract from your own happiness.
That is the only way you can attract those who can *truly* benefit from your help.