Love thy neighbor isn't what I was talking about, and as someone else pointed out, your interpretation of that to be fellow Christians is incorrect (although in real life a lot of Christians behave how you say and worse).

Similarities between Islam and Christianity are to be expected. Islam is an appendix (The Quran) to Christianity (The New Testament/Covenant), added about 700 AD. And both are appended to Judaism (the Old Testament/Covenant).