All more of less true - but even so, you can't look at the Crusades as "yarrr! attack".
Indeed! My apologies if that didn't come across clearly.

This is emphasised even further by Arab historiography, who didn't regard the Crusaders as that much as an alien force, but rather as a continuation of a long series of Byzantine attacks against the Syrian domain. To that effect, various Arab Caliphs, Sultans, and Emirs regarded the Byzantine Emperor as the spokesman for the Crusaders and would rather go to them.

The Crusades didn't really make that much of an impact on the Muslim world as a whole: they were regarded as yet another player in an already troubled field. The Seljuq Empire was falling apart, various kingdoms had declared independence throughout the region and when Muhammad Shah sent an army to relieve or reconquer Jerusalem, it was destroyed. Not by Christian armies, but rather by the Muslim Emirate of Mosul.