So you’re offended by an anti-Trump car sticker? You need to get out more | Tim Dowling

We are now used to the idea that our online social spaces are a haven for gratuitous offence. Giving offence is seen as a right; taking offence a weakness. In situations where people are taking sides, offence is met with counter-offence, the coarser the better. Our virtual public forums are toxic environments.

But what about actual public space, or what we used to describe in the old days as “going outside”? In public, especially in the US, attitudes towards offence have grown correspondingly prim, and the long-established boundaries between offence and free speech are being redrawn.

In Texas last week, a Fort Bend County sheriff posted a picture of a truck on his Facebook page in a bid to trace the owner. The reason was the large writing on the truck’s rear window, which most American newspapers rendered as: “F–k Trump and f–k you for voting for him.”

The sheriff said the sentiment constituted prosecutable disorderly conduct, although the district attorney said it didn’t, while the American Civil Liberties Union insisted it was constitutionally protected speech. The owner was subsequently arrested – on unrelated charges – and released. She and her family have been the victims of online attacks by people who have taken offence at a window sticker on a truck they will never see.

The case is related in spirit, if not in law, to the saga of the cyclist who gave Trump’s motorcade the finger last month, and was fired from her job. The fuss was caused by a photo of Juli Briskman that later went viral, and her employer’s excuse for sacking her was that she re-posted the “obscene” image on her own Twitter account.

Briskman has also been the subject of vicious and misogynistic attacks online, from those presumably offended on the president’s behalf. But the original gesture was a public one – the kind of thing that happens between frustrated strangers at road junctions the world over. It’s the sort of easygoing disrespect that once defined going outside, into the space that everybody owns and nobody owns. Once we knew how to negotiate that space. Maybe we don’t spend enough time in it anymore.

In-flight entertainment

Which brings me to the giant penis in the sky. If you know about it at all, you will have seen the image online at the weekend: a huge penile outline – with testicles – drawn using the condensation trail of a US military aircraft. About 2,500 people from Okanogan county in Washington state had a brief opportunity to be offended by it, although I can’t find any accounts of actual outrage – and one has to assume the locals are the source of all those gleefully retweeted pics.

I will admit that my first reaction to the image was: skill. I think all trainee pilots should be able to trace a passable penis in the sky before they graduate. The US navy thought different: it apologised for “this irresponsible and immature act”, and grounded the air crew of the E/A-18 Growler responsible. But I have to say that this is my kind of public offence: immature, irresponsible and absolutely massive. If there’s a better use of the $67m fighter jet, I can’t think of it.

Spirit in the sky

The giant skydong of Okanogan county is by no means the first time such an airborne apparition has occurred. On the military and veterans website Task & Purpose, a blog titled A (Very) Short History of Military Personnel Drawing Dicks in the Sky points out that in 2014 a giant penis appeared over RAF Lossiemouth in Scotland. In that case, an investigation found the penis was not an intentional prank or provocation, but was drawn accidentally while the pilot was flying in a holding pattern waiting to land. “People sometimes look into the sky and see all sorts of things,” said the RAF at the time. That they do.

• Tim Dowling is a Guardian columnist