What's with this whole "blind patriotism" thing?

Why do so many people think it's a necessity to love the country one lives in? Whether it's actually good or not, part of freedom is being free to dislike something and express that dislike. Americans in particular lose their shit when someone dares to say America isn't a perfect utopia. I mean, I live there. The part I live in is nice enough, but we've got some serious flaws. It's fine to love your country, just don't shit on others for not feeling the same way.

*loses all my SW friends for being political*