They're not any less trustworthy than the general public. Usually you should be skeptical of people professing to be altruistic, however.

You cannot become a billionaire by being ethical. That's just not how capitalism works in practice. You can only become a billionaire through exploitation. So yes, they're one of the least trustworthy people because their interests do not align with those of ordinary people.

This is simply false.

Business is a social resource allocation game. If you break the rules you will be punished.