In that case he would do way too much dmg, but you forget that
a) Armor damage reduction has an attacker level component
b) He still uses a shield
You can expect him to get close to the 75% reduction cap. If he got hit for 35, we’re talking up to 140 against 0 armor. The lvl 19 druid from the video has 1808 armor, which should be like 45% DR on that level (just an educated guess), and he takes 45-80 dmg, which seems right. (140*0.55 = 77)
tl;dr: from video evidence in this thread the dmg is correct.