hk is a former colony of the UK and they ask all western countries for support, also germany...one of the protest leaders joshua wong also spoke to germans on german television (and he speaks german)... the treaty that gave hk back to china should give hk 50 years of autonomy and china may not interfere in hk autonomy and this is broken, which is why hk feels like the only one they can turn to is the west...
also this is not a protest of a few thousand as it was in syria but this is 25% of the country that is currently protesting actively for months... when 25% of a population strongly disagree about the issue enough to stay on trhe street for 4 months then it should not be debatable...
because they are protesting the police marks them with blue water to later imprison them, and there are mobs beating them down... they fear that the little democratic leavarage they have (as elections only decide half of the government seats) will be taken away (hence umbrella movement) and protestors as a result were banned from running for government office (realizing their fears).. yet also freedom of speech is being limited there as book shop owners get kidnapped into china for selling books about the cultural revolution and mao zhedong in china, and the extradition treaty would mean people could get extradited for protesting to china...
also keep in mind an extradition treaty is usually done between countries of similar justice system while china doesnt even have a fair justice system...
hk is also refuge for many religions that are banned in china, groups like uigurs (muslim) and falun gong (its like yoga buddhism) flee to southern asia to not get put in concentration camps...
talk about foreign support. hk leader was inviting chinese troops for "foreign support" and the military was placed right at the door step of china to march in at any time.