Originally Posted by Foltan

I do feel sorry for you, rudeness is never acceptable regardless of what you may or may not have done.

As a general note, are you aware that E-gates are manned by humans? A lot of people don't realise this and get angry when they're closed. A border force agent still views the passports and images, but they're able to monitor multiple gates a once, so if you don't have staff available then you can't open them.
That doesn't excuse them for being understaffed obviously! But it's useful to bear in mind.