To the best of my knowledge Tatars had political motives. They did not spread jihad. And definitely they weren’t terrorists. These were normal territorial wars. Calling to fight “against christians” had different conotations than today. Yes, it was violence as every war is. But these were periods of formation of states in that region. I would like to repeat that overall experience in Eastern Europe of coexistance with Muslims is not negative. Central and Eastern Europeans were not oppresing them but to the contrary trying to help them be educated and merge into the society. I think we can compare early period of wars to the time of maturing. However today there is no excuse to come back to such primitive culture. The problem is, this is dr Jasser point as I understand it, that radicals are trying to have renewal of this Middle Ages practice. But not everyone is radical. Bernard Lewis makes good distinction between them and moderates.
I don’t claim to be an expert on the history of the region.
However, I think any society basing its economy on slave raids into neighboring areas can be legitimately called terroristic, though that is projecting today’s categories back into the past, which is inherently problematic.
YMMV