He didnt generalize, he exposed the truth - suicide bominbings on civilian infrastructure and mosques in the world has a higher % (relative to their population), of Sunnis than Shia, and this is amongst the exremists in both camps. As a %, it seems Sunni militant groups do more suicide bombings on mosques and civilians than Shiite militant groups, so
@TheImmortal is correct - calling his argument a generalization is not logical, he didnt generalize anything - he extricated a clear pattern of the demographics of this bad act and how there is big gap between which types of Muslim extremists carry them out- the vast majority seems to be Sunni (vs SHiites, which barely do them). Its a sensitive topic, so lets stick to the facts and truths. no fallacies either.