The reason is because pack n plays are not easily sanitized. I used to work as a regulator and non-porous surfaces (wood) can and should be sprayed down regularly with a chlorine solution to disinfect. Porous surfaces must be sanitized properly in a washing machine with a diluted bleach solution. Since you cannot break down the soft porous sides of a pack n play to wash in a washing machine, it is not easily cleanable. For example, if a child is infected with norovirus and he vomits during nap time on the side of the crib, how would someone properly clean and sanitize the mesh sides? I suppose you could hose it down outside and spray it with a chlorine solution, but it's not easily cleanable. Let's say it happened at the first nap and there is a different child coming in the afternoon who needs that crib for sleeping. How would you have it properly cleaned in time?
I understand why so many use them, but I personally don't like using them with the exception of my own children when we are on a trip. I much prefer wooden cribs that can be cleaned easily. Just my 2 cents
