Again, there seems to be a misunderstanding. Exploring in pwcf on no military is allowed and is perfectly fine. The only question is if it is also perfectly fine for a kd with no cf to hit the kingdom who is exploring on no military. Emeriti debated this and decided that it was not appropriate for a kingdom in their position to vulture BB since their kingdom could just war them after.
Bours kingdom though was much weaker but had the #1 province and a few other big ones. Bours kingdom could not stand a chance to war them after BB trained up or even fight them after. Emeriti wanted Bour to get a cf with BB. Emeriti suggested that if BB was not giving him one he could force one by razing. Emeriti did not want bour to raze BB to help Emeriti's position and only wanted Bour to get his own cf. Right from the start, bour offered BB extra free land and then even free gc and a fake hostile in order to try and get himself a cf. None of these things would have helped Emeriti.
The only reason emeriti appeared to end up benefitting from the situation is because BB refused all of Bour's offers and instead decided they wanted to crush him. As part of this, they gave Emeriti a longer cf than they otherwise planned to. It should be clear though, that Bour offered BB stuff that would have helped BB's position relative to Emeriti had BB just cf'd him and accepted it. This was not done for Emeriti even though it was done in part on the advice of Emeriti on how Bour could get himself a CF.