There are two issues here. Firstly, whether the grip by Blue is dangerous. In which case it should be Matte. The second is whether the move should be allowed to continue IF the grip was not deemed dangerous.
Both Alexander Iaskevitch and Daniel Lascau say the grip is dangerous. In which case, it should be Matte. However, Juan Barcos points out that if the grip were deemed to be not dangerous, the action should be allowed to continue, in which case, it would be Ippon.