This was the different between Zenith and Zander. The former was too blunt, but the latter was being sneaky. Zander liked to do thing very subtly.
Zenith knew about king Rowan's intention on Zaya and he was not the least happy about it, thus his solution was to kick him out, because he saw him a nuisance for their little sister, but Zander couldn't do that. He had a reason and plan to get Marca El involved.
He needed to get them to their side before the people from Holy Kingdom did that, or else, they wouldn't stand a chance to fight against the Holy Kingdom if it came to that.
The movement and the relationship between Ogregon kingdom and Holy Kingdom had been very strain for as long as Zander could remember and now, his spies reported that the latter had been very shady and the last report said that they had been in contact with the west, to Vemion to be exact.
It was as clear as day what their intention was.