Would you be angry if someone associated you with the belief in Blue Ferries? Or would you simple say, "whatever". Both are irrational in the mind of an Atheist. But only the association with the belief in God evokes anger.
This reminds me of working in public service. There would be various questions that employees would have to answer many, many times in any given day, despite there being lots of signs around in an attempt to inform people.
Personally, my belief is that signs are for ignoring, and thus I rarely got irritated with answering the same question over and over.
But plenty of people who were happy to answer it the first time were quite exasperated by the 1,000th time.
Now, I believe that blue ferries exist, but I imagine those who don't might get irritated if half the population assumed (and oftentimes publicly stated) they were amoral because they didn't believe in a certain type of ship painted blue.