As have I, and when those two were released I thought it was an odd move. Those two players as you observe don’t really cost against the cap as they are not top 51 contracts. Both were little more than PS players or camp bodies so there must have been something else.
Perhaps there are other reasons unrelated to cap or ability. The team is usually not very forthcoming about things like that. Maybe they didn't get along with coaches or other players or something similar or unreported.
My coaches/other players comment was me putting a hoped for positive spin on a curious situation.