I think the larger issue that everyone has with it being an invasion as opposed to a war of liberation is the time difference. It was not an immediate reaction to Manzikert, Yarmuk had had happened hundreds of years before so it was NOT a reaction to islamic aggression of even the same decade. Even the Byzantines who at first were okay with the crusades helping them reclaim parts of anatolia didn't want the crusaders to continue on and make war with the fatmids.

It's not like the decade following the last Ottoman siege of Vienna during which it's expanse was gradually pushed back to the southern balkans, there was no immediate reaction to any major event at the time that made the muslim threat greater than immediately after manzikurt. The reason the first crusade was even successful is largely due to the fact that there was so much turkoman infighting that no major concerted response was able to happen until the siege of Antioch.

I'll agree with the premise that the crusades were good for western civilization in it's export of unlanded younger sons and a general renewing of trade and cultural ties with the near east, but to white wash it is silly. The time period was absolutely brutal for minorities no matter where. Was the looting and pillaging of jewish villages within 'germany' on the way to the crusades justified in any way? The crusaders were for the most part appallingly ignorant which is one of the reasons the later crusaders couldn't understand why their comrades within the Kingdom of Jerusalem, Tripoli, or Antioch were not so keen on making war on all the surrounding muslims. None of this excuses the outrages that were committed against christian minorities but it in the context of the period was totally normal. Bear in mind that last pagans of northern europe were and would continue to be 'converted' to christianity for quite some time.

I think you'd do better trying to determine what the acceptable time limitations are for liberating an ethnic/cultural/or coreligionist people. I could feel justified in a war against 'Islamic State' for the outrages that they have and continue to do, I could not feel justified in a war against Tunisia or Algeria for the crimes of the Barbary Coast states 200 years ago. The amount of time past does matter. Your broad definition is like the Chinese claiming the whole of East Asia because of the Qing Empire's previous hegemony there.