"What is an airport, which is not a church, doing with prayer rooms and a chaplain in the first place?"

The prayer room is most likely there to ensure that Muslim passengers have a place to do their daily prayers. A Muslim chaplain was probably included for the purposes of doing Friday prayers and Ramadan and the like. Then I suspect that all the Christian chaplains got added because the Christian majority felt left out and would make a fuss.

All that being said, the prayer room is available to people of all faiths and none and is a place for people to quietly contemplate as well as get away from the noise and bustle around the airport. I understand chaplains also help with bereavements when bodies of those killed in Afghanistan or Iraq are sent back.

"Secondly, are theists in the U.S. or England punished with criminal prosecution for passing out literature or otherwise proselytizing in secular locations?"

If it's harassment then yes. I have given the example above that Stephen Green (leader of the small but noisy fundamentalist group "Christian Voice") was arrested when he was giving out homophobic leaflets during a gay pride march.

Similarly if religious pamphlets going on about how unbelievers were going to hell were regularly left at a hall used for humanist meetings that would also constitute harassment.

Naturally a single case of such harassment in either case would only warrant a warning. The problem in the case of the OP is that the guy had done this so often that we have a record of him doing the same thing in a Church and of unplugging a sound system playing Christmas music in his local Tesco. That means that he undoubtedly did this sort of thing very often.

Accepting nontheists doesn't give them the right to harass people in prayer rooms. That would be a very bizarre form of "acceptance".

"the KKK and neo-Nazi groups to hold rallies without being arrested, and the like? Why?"

Because they do it in the public square and not at some poor family's funeral of course. That's the difference between free speech and harassment. One is expressing yourself publically and the other is invading another person's private space. Is this really so difficult to understand?

"Yelling about fags at funerals is religious expression - that's how they see it. "

If they want to see it as religious expression they are welcome to. The fact is, however, that it is also harassment and the courts have a duty to protect citizens from harassment.

If what you are doing is blatant harassment, you don't get to turn around and say "but it's my religious (or atheistic) expression!" Harassment isn't protected in the the UK.

"since percentage-wise, there are so many of them"

3% isn't really that many.

"If airports have chapels, I demand atheists get their own room where they can watch Dawkins on youtube and drink cocktails. "

This remind me of the child on father's day complaining that there isn't a children's day.

Dude - pretty much every room is a "watch Dawkins and drink cocktails" room. The idea of the prayer room is that it is a place for people to silently contemplate/meditate/pray/tell-the-whining-brats-to-get-the-hell-out. Naturally it is not a separate room for Muslims-only, but is for people of all faiths and none to express their spirituality/collect their thoughts.

"There was no mention of his previous activism."

Activism? Is that what we're calling it?

"Let's just hope no one in England thinks atheist speech is harassment."

That's not how harassment works. Harassment actually has a pretty clear definition.

I mean seriously, surely you can tell the difference between expressing your opinion in the public sphere on the one hand and picketing funerals or spending all week long shouting at people as they enter their local abortion clinic on the other?

I'm not even saing that the airport thing isn't worth discussing. It is. However, it's a mistake to suggest that the chaplain said "I'm offended" and then the guy got thrown in jail. What happened was that a disturbed individual was making a habit of going into places of worship and leaving intentionally offensive material to the extent that he had been in court for this behaviour at least twice already. This didn't come out of the blue and I think this guy probably has issues.

Googling "airport chaplain" the very first link is for Manchester Airport chaplaincy. See what you think: http://www.thechaplaincy-manchesterairport.co.uk/

It's not about letting the authorities decide what is free speech. It's about letting the courts decide what is harassment. Surely it's not controversial whatsoever to class picketing funerals as harassment, is it?