"They watched, like adults should". Who said these were the rules? Are you in charge of the world? @ExtraHotDoubleShot that would be sad world indeed!
You've called people sad, and silly, and described them as having 'issues'.
Yes - their issues are that they have empathy, feelings of warmth and like to express them, acknowledge their own innate needs to connect with life and nature, enjoy a chance they might never have had as a child to feel the feathery down of a duckling or the ticklish nibbling of a goats mouth (and the nip if you let it!).
There are people who grew up too early with the responsibility for always letting younger siblings be at the front and have their turn - not people living in abuse, just in normal families. There are people for whom childish joy was lost too early. They don't have 'issues' they simply didn't have the opportunities that others had.
On a personal basis there is small thrill that I get from interacting with nature, including animals. I love seeing my dgc have that experience but it doesn't lessen what I might also feel. I can observe dgc experiencing something but the giggle of doing it myself is also joy - and we should all have a joyous day out together. Of course if there were 3 or 4 or 5 children fretting a queue behind me, I'd most likely let them go before me, but I'm not going to stand back and let every child in the park go ahead - eventually I do want the experience for myself.
@ExtraHotDoubleShot I don't know whether your were the most fortunate child who lived with pets, had young animals (chicks, kittens, foals) nearby and therefore you cannot empathise with any current adult who didn't experience any of these, and might crave the once-in-a-lifetime experience; or whether you were a child who learnt that you stand back, let others have their turn first, whether you learnt that once you grew out of being the age of a child it wasn't OK to enjoy or prioritise childish things for yourself.