Basically what the OP is "reporting" is a rumor. Rumors like "OMG lvl 3s are sooo hard!!" do nothing to further the gaming experience and serve no purpose other than to attract flames and cause hue and cry over nothing.
This "person" who told you about this? Ask him what he was doing. 9 times out of 10 a lvl 20 being killed by lvl 3 mobs can be attributed to a noob player - NOT a "flaw" in GW's gameplaying dynamic.
You *should* concentrate on work, and remember not to believe everything you hear in-game.
Anecdote:
Right after the release of factions, I decided that I would have a little fun. So I stood in Hero's Audience, Seeker's Passage and Dunes of Despair and spammed in local chat:
"Paying 3K for runner to Amon Rarth - new desert town"
You wouldnt believe the number of PMs I got saying "where is it" or "I'll take you for 5K".