The reason that it was bad was that John wanted to be disrupted because he saw that waste space Stibbs selfishly kept to himself not as the perfect site for three homes but as the perfect place for his self-indulgent need to inflict his eyesore model train layout on an unhappy world. Imagine how terrible it would be if Mike had to do what he did and start from scratch; far better to give him the family farm like a good little plowhand.
That would be just as bad as simply talking to April like an adult and explaining that since the fire made Mike, Dee and the Patterspawn kinda screwy, it would have next to impossible for any of them to see moving anywhere soon. That way, he could have got her on board and not been able to grouse about selfish kids. You can see how bad that would have been.