Camouflage.

I'm sure everyone wants to be the good guy. The guy who just strikes everyone as the nice one and the decent one. The guy who just says whatever people want to hear. The guy who just does whatever people want to see. And I'm also sure that there are enough of you who already are that person.

Hello there, I'm the Earthian.

To do that is the most comfortable thing for a person. If you think about it, the deeds done from this mindset is plainly selfish because at some point in his life, when he does actually get hurt, he'll have people feeling obligated to help him out of that.
At the end of the day, it's all about strategically planning and executing his own ulterior motives. It works because he never has to show his true identity and to top that off, there will be few who will get suspicious.
People call it adapting to the situation. You become what your situation asks you to be or what your situation molds you to be. Think of the analogy that incorporates the chameleon. A more colloquial term for this would be "doing what's best for business".

I'm not the one to say if this is right or wrong. You judge. I'm just going to say that being right, following your conscience is way harder. It's a lot more demanding. Which is probably why we make nonsensical excuses for all the ill-activities we do and even justify them.

Lots of love, peace.