The reason is simple, since no one seems to know what 
actually means, and there are other symbols available that cause much less (i.e. no) confusion, it is time to retire the notion of a natural number.
Let me explain. Everyone in mathematics seems to have their own opinion on whether 0 is a natural number, which is absolutely fine, it really is. But every one seems to regard their convention as obvious, self-evident and universal, which isn’t fine, because this means that they don’t seem to feel a need to actually tell anyone which convention they are using. Leaving their readers, students, etc. to guess what they mean. which causes confusion.
So, what symbols to use instead? Simple, 
for the (strictly) postive integers and 
for the non-negative integers. Each of these symbols are unambiguous and consistent and can both be used in the same document without having to change conventions.
QED.