If your first year baby gets sick and never recovers from the infection, what are you left with? Same with second year. If the plants are under stress/attack from a disease issue, they are spending energy to combat that issue and not making healthy growth. If they are kept healthy from the beginning, they can continue to make growth at their own pace. The whole notion of 'leaving everything grow' for the first year is correct in that the more photosynthetic area you allow the plant to produce will allow it to make more energy for itself, but hops are VERY efficient when it comes to making an excess for themselves. After working with plants since earning a degree in plant science way back in '82, I'd much rather have a healthy plant and allow it to grow at it's own pace rather than try to push it, just me though.