About Throwing Pearls to Swine

My pastor and I had a discussion some time ago about this verse in Matt. 7:6 -

“Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and turn and tear you to pieces.”

He expressed disagreement with the common interpretation that the verse means you should not waste time with people who are rejecting your Gospel of the kingdom. He says, no, you don't leave them alone, because they are the ones you exactly are reaching out to.  Thus, if you believe this commonly believed meaning, you may actually be doing it wrong.

What is True Altruism?

One time as I decided to research on altruism on the Net, I found myself disturbed by other people's impressions. Some comments define altruism as "the desire to please others." I found it disagreeable because I hate pleasing other people. Yeah, no kidding, it's one of the things I hate doing the most. But aside from that, I've heard people advise, stop trying to please everybody. In addition, pleasing others in not necessarily doing good. I agree with this. But why is pleasing others not necessarily good? Isn't that a show of love of others in the Christian manner, as some would say?