One, Roura's comments sounded like they were intended to convey that lineups are determined by availability and form not contracts.
Two, even under Guardiola the season before, Thiago failed to hit the 60% threshold and was available for 18 million as well. There was little in the way of controversy or moving on because the player (And presumably agent/father) had no intentions of giving up.
Three, I despise Rosell but I don't believe for a second that he, Zubi or anyone with the board was oblivious to contract clauses - on the contrary, they are ruthlessly efficient when it comes to numbers.
Rosell is fairly calculated, IMHO. Moves are planned out, far in advance and so I find it implausible that Thiago's clause snuck up on anyone two years in a row.
Furthermore, what is also clear is that the board is doing nothing to try and entice Thiago to stay through an improved contract etc. which makes me believe they are either trying to profit off the player's sale or engaged in some sort of Mexican standoff over contract improvement. Irregardless, it's inexcusable that it's being handled this way, IMO, and would've never happened under Laporta