And Stalin was an atheist
Whoever it was it most certainly was not Yaron Brook! And there's not that many people at the ARI either. What exactly did he say? Sometimes we have an ear for hearing we want to hear. Did the person really say "it's immoral to give to charity" (i.e. you are not allowed to do it) or the actual Objectivist view, that held by Ayn Rand herself, that it is morally neutral (that you don't have to do it)? If it's your personal opinion that charity (or forced redistribution of wealth) is a moral obligation and you have certain preconceived ideas about what an Objectivist should say it's possible that you may have misunderstood what was said. Or rather heard what you wanted to hear.
Excuse my skepticism but I just don't believe anyone from the ARI would phrase it the way you claim they did. Read Ayn Rand's own words, I provided you with a link. You claimed earlier that Ayn Rand is the first and foremost voice on Objectivism (not so unreasonable) so the link I provided should show you what the Objectivist's view of charity is: morally neutral, allowed but not obligatory. That's the view that I share. What about your friend?