He thinks they need to. Once one group starts getting stalked and watched and oppressed, it will seem fine and acceptable to the common people. That word will spread. They'll have a new group to harass the way mages have been harassed, and he believes that no group should be treated like that.

Even worse, news that they're being suspected and watched at all times could cause fear to spread and get rifters and shard-bearing natives killed.

At the end of the day, they're all people, individually accountable. Not a faceless lump of a group.