"Impossible to conceal" is the only "self-evident" thing about them. That they take a lot of training and strength to use is empathetically not self-evident to people who have never handled a bow.
That gets said a lot about guns, but in truth, it takes a very special level of negligence to cause a situation where a toddler or a pet will be dangerous around one. In fact, majority of people who've never handled a gun will have either widely exaggerated belief of their danger (due to scare stories like yours) or widely underestimate the danger (because their only contact with guns is pop-fiction and they don't even know what a real gunshot sounds like).Meanwhile, even a toddler or pet can be a mortal danger around a gun. So it makes little sense to me that the wizards' dismissal of them is born purely of ignorance or stupidity.
Let's appreciate that neither Intelligence nor Wisdom are primary ability scores for Harry Potter Wizards, so the average Wizard will not be any smarter about guns than your average gun-ignorant muggle. Now look at hiw stupid gun-ignorant muggles can be about guns.