Sorry, wrong answer. The left fully understands the dangers Islam poses to their way of life. However, they have a bigger enemy to deal with first: Western Civ/democratic capitalism.
Hitler signed his pact with Stalin so that Germany could first focus on the Western front. So too do liberals hope to take out Western Civ, thus creating the new socialist man, before they turn their attentions to the Islamic threat.
The entire thrust of the Dem's anti-war logic is that it's "our fault" ie the West's history of exploitation has caused turd-worlders to "hate us". This strategy to upset America's war effort & take back political control is NOT based on some naive assessment of Islam.
I agree with your assessment and if they are successful in defeating Western Democracy they will ignore the "Rules of Engagement" they insist we follow and mercilessly destroy or make slaves of all Muslims.