You can block from hand because ignore only targets cards that are in play (used to be different). However, once the card hits the table, it is subject to being ignored if it still meets the specifications.
One example where this might not be the case is The Garden Tomb.
TGT: “If opponent has a Redeemed Soul, then Salome, Mary Magdalene, Joanna, Peter, John, and Mary the Mother of James ignore all evil brigades that do not have at least two characters in play.”
If you have a Redeemed Soul and only one black brigade EC in play (opponent has none) and your opponent attacks with Peter, the EC in territory is being ignored and cannot enter battle. However, you can block from hand with a black EC at which point there are two black ECs in play and neither of them are being ignored (Lot’s Wife or Delilah could then potentially band to the EC in territory as well).
