the skill that refer to % critical resistance r bugged (localization issue). just ignore the % symbol and all works fine.
for example, d/r according to tooltip can decrease the target critical resistance by 1790%. the correct tooltip is to reduce it by 1790.
so if the target is a player, u can see its crit resist values dropped by alot in Character tab, especially handy when the enemy is honor gear (with high crit resist values). on bosses it works same way. they have inherent crit resistance values with can drop according to proper debuffs, allowing the party to crit more often on them.
there is a formula that relates the crit resistance values of the target with your level difference and ur crit rate (number, not %), so to result in the final % chance that u have to crit on target.
in general crit resistance reduces only ur likelihood to crit on the target. if u manage to crit, the crit dmg is unaffected.