Walker did feel bad that Ventus was being tested so much, however, as he looked at the people that had gathered because she asked, he wondered why else she had looked in to those who could use curses.
There weren't just a few, Walker had managed to find ten. Apparently the wind dragonkin had been researching this for her. It proved that there were multiple classes that could use some form of curses that were not as simple as debuffs. On top of this, they were also of multiple races.
The demons could be understood since they had both caused curses and also been under curses. As they were from a race that had been tortured by itself for some time. Not to mention being known for this even though it was not actually as common as the fears of others had been.