Cus Islam as opposed to Chritians or Catholics beleived in learning,cleanliness,healthy eating,and a strong belief to be a united people.Actually healing the sick instead of throwing them out.
Many other cultures were sick of the bs goin on in their own countries,and heard of the strides Islam was makin,and wanted to be a part of the progressive future,and not held back by their less informed and knowledgeable leaders.
The others were dirty unlearned barbarians,,who had no idea what "culture" or "civilization" meant.
We can thank the Muslims/Islams for the way our culture and the way the world worx today.
Mind you,,i cant say the same for them in recent history...they seem to have de-volved where the rest of the modern world evolved ;(