If chlamydia can be spread through oral sex then why cant it be spread through saliva as lube for a handjob? what's the difference? also why isnt it a risk from kissing but is a risk with receiving oral? trying to understand what makes it transmit?

Your premise is wrong: In fact, chlamydia is rarely spread by oral sex. It's understandable that you're confused on this; there is a whole lot of mistaken information online. But chlamydia rarely infects the mouth or throat, and when it does the organism is present in too small amounts to be passed by oral sex or kissing. CDC even recommends against ever testing for oral chlamydia. No worries!