It's not that I don't want to acknowledge it, it's just that opening the multitasking switcher is just as simple.
OK, let me sum this up again.
I receive an email that contains an URL. I click the URL, grab whatever info I need and want to close that tab and go back to reply to that email.
In iOS, I'd have to press the tab button and click the - to close that tab, then double-click the home button and press mail to go back to the originating email. That's 5 button presses.
In Android, press back. One button press and that tab is closed and I'm back in the originating email.