What I don't get is the number of intra-European flights still being operated in that reduced schedule. Do they expect there's enough connecting passengers on those to operate HND? As per the most recent update by the Ministry of the Interior, there's basically no business to conduct outside the borders, unless it's absolutely essential or you're e.g. doing maintenance in Kilpilahti or Hästholmen.
Thankfully my LHR-HEL flight will be cancelled, but my outbound HEL-LHR is still operated, although with a smaller plane.