@Ast007,

Because it is difficult to read.
>Why?
>>Please stop top-posting.

and...

Because it messes up the order in which people normally read text.
> Why is top-posting such a bad thing?
>> Top-posting.
>>> What is the most annoying thing in electronic communication?

and...

Maybe because some people are too annoyed by top-posting.
> Why do I not get an answer to my question(s)?

Regarding your question...

The USB socket has four contacts. The two edge contacts are power and the two middle ones are data. In case of dumb chargers the two data contacts are shortened by the charger, indicating to the USB device that this is a charger.

If your phone detects a short circuit on the data pins, it goes, "aha, I am on the charger, hurray, nom nom nom!" - and the software displays the charging icon in the status bar. BUT, if one of the power pins is broken, it does not actually get any power so your battery is not being charged.

Simple as that.