We don't even know to what exact extent the news article is really telling us what's happening there, as the article is based on a leaked FIO document, mainly.
It seems the Sarum Family has been building flotillas of transport barges and trained small-sized squads, but we don't know yet how Merimeth intends to use them, other than the allegations of the leaked FIO report.
So, to begin with, we don't even know whether this is really meant to be for the purpose of slave raids. Also, even if it's for slave raids, it doesn't mean that the Empress is cool with it, as Samira pointed out, because the Empress is not the head of House Sarum and might speak out against Merimeth's intentions. I doubt so, though.
Now, even if Merimeth intends to raid for slaves, of course those opposed to the Amarr will claim that Amarr could go nuts and attempt to raid any territory the empire has the loosest claim to. That is something they already do, though, it's nothing new. They're claiming it all the time and of course they will claim that these actions show that they have been right all along.
Now, then, so be it. I don't see how that is much of a change, though. I, meanwhile, am happy to see something happening in Amarr.