The goal of the anti-Islamist is not to give you the context or an exegesis but rather, a distorted view of Islam. It is an attempt to present a truth about Islam in a negative light. The most common way this is done is by removing surrounding material crucial to the context of a particular verse.
To not fall prey to this trick one should look at every verse contextually to find its truest meaning. The simplest way to do this is to examine everything that comes before and after the verse. A minimum of 3-5 verses is good starting point.