"Qassams are always fired as a retaliation to the IDF shelling and invasion to neighbouring Pals villiges" This is a massive ploy used to justify their terrorist behavior. Not surprising that you mention this as an excuse because it's the only opinion you every see in Amman. I can point to many, many moments of silence, when the PRC or IJ fired qassams into Israel. If the IDF wasn't raiding a village, then what was the excuse? "...to torpedo a peace deal between Pals and Israel", "...a present for Ramadan...", etc. Often, they use an excuse many months old. If the weapons was used as a defensive, then why aim it solely at civilians who serve no military purpose in Israel. Terror, pure and simple. When Gazans see what West Bank peace causes the IDF to do, they too will ask "why the qassams??"
from the article: Repay Gaza in kind