I can't say for sure but the wording Amica chose seems to suggest that the person came belittling and arguing against the tenants of Islam during the holy month, with no instigation. These situations happen, especially given the amount of misinformation out there. If someone genuinely wants information on these topics, and calmly asks about them, usually all parties go home feeling better. When someone attacks both the follower and the religion with mocking and aggressive speech/actions, it tends to get heated. And no matter how much you put effort into disproving with any amount of evidence the aggressor will usually just continue their tirade. Now that... I have witnesses numerous times.
I was on a plane once and a man was talking to me (I'm usually a private person) about things he dislikes, and his religious views. He said he never gives to charity, to which I found strange Given this man had been talking for 15 minutes non-stop about being a good Christian man. So I said My religion is Islam, and we have both required charity and optional charity, and from my past I don't see why any Christian would be happy to give charity. His response (in a way that indicated he didn't expect me to know about the story) "If you give a man a fish you feed him for a day, Teach a man to fish and you feed him for a lifetime". I went on to explain how I think he misinterpreted the line and he mostly agreed (though I doubt I changed his life). Which is fine. He went on to ask some questions that he had on Islam (the regular: 72 virgins, Jesus not a savior, and killing the non-believers) and I felt when I landed he understood more, and definitely felt much less hatred than when he got on.
On the other hand A man like my father's cousin seems to have found a great need to attempt the yell about how horrible Islam is to the world on my FB wall. Time and time again, he asks 20 questions he copy and pastes from hate sites, then when I answer them he says I'm lying because that is encouraged... I ask him where is it encouraged... he quotes a site that has no references and no affiliation to anything Islamic, but rather an anti-Islam site dedicated to proving that the Government did do 9/11, but they had Muslims launching the missiles... after about a month of back and forth I haven't been able to contact him for about a year now. These are the types that make understanding impossible, and If I read Amica correctly, the type of person the Croatian Woman was.