From my experience, humans have an advantage over dretches '1 on 1.' Yes, good dretches won't approach you from long distances, but even so, it's still possible to dodge dretches in close quarters. In fact, during all the 1v1 practice sessions I've held with people, humans almost always win, because the human never lets the alien get a goon (or if so, one goon maximum). Humans aren't exactly screwed after one headbite - it takes two to kill a human. Just don't let the dretch bite you twice. Same for the dretches - don't let a human rifle you 5 times.
I can understand camping if the opposing team has 2-3 dragoons, but camping against dretches is unheard of in high level games. Humans are far from being THAT base dependent.
About this tournament: it is pretty silly to dub this the 'promod.' From what I saw of the one video I watched, it looked like the aliens were camping the domination point, instead of the human base entrances. Hence, it does not seem to prevent camping as claimed - just base camping. Call this the domination tournament or something.