Q: Unable to close active apps via home button

Double Tap the Home Button... Then swipe the App Upwards.

See here  >  http://support.apple.com/kb/ht5137

From Here  >  http://support.apple.com/kb/HT4211

Those who have not experienced the problem will tell you to double tap the home button. I have had the same problem where holding the home button won't bring up Siri and double tapping or single tapping the home button won't close, quit or do anything to the currently running app.

Your problem sounds more like a malfunction of the home button rather than the threads you are hijacking about closing apps in the multi-tasking bar. It sounds like you need to make an appointment at the Apple store to have your device checked.

Thanks for your input Chris. Your insightful input brought it home for me.  After consulting with the apple experts, they hinted that it might be a software issue. Thanks for the suggestion.