Homeland includes themes that are relevant in modern society. In recent events, the terorist group ISIS has sparked the interest of many Americans. Social media is evidence that Americans are curious about what is happening around the world and shows like Homeland give them a glimpse into what homeland security and terrorism looks like.
Yes, when a topic is dramatized in popular culture it usually spurs debate and contraversy in real life. People will begin to hear things in the news about Homeland security and they will confuse it with the dramatized version on the television program. This happens with many things and I believe especially government.
Homeland is the first show to really tackle the homeland security issues that face the United States without over-the-top and hard-to-believe theatrics. It's large following and various accolades have earned a lot of attention over the years. Certainly major networks are going to want to take advantage of that fan base and draw them over to their networks with similar shows.
Homeland is great show, but it's not the start of something big. Its audience love it, but a lot of people don't want to watch a show about fears that could actually come true. It's much more fun to watch a nice bit of escapism like the comic book adaptations coming out at the moment - shows which have the same tensions, and great characters, but which allow people to look at them from a distance.